4211(75-87).pdf ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 75 MOOSE DETECTION DISTANCES ON HIGHWAYS AT NIGHT Arthur R. Rodgers1 and Patrick J. Robins2 1Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, 955 Oliver Road, Thunder Bay, ON, Canada P7B 5E1; 2Forensic Engineering Inc., 1439 Legion Road, Burlington, ON, Canada L7S 1T6 ABSTRACT: Moose-vehicle collisions are a serious concern in many areas of North America and Fennoscandia. In northwestern Ontario, more than 400 moose-vehicle collisions occur annually, and 26 fatal collisions have occurred over the last 10 years. To avoid colliding with a moose, a motorist must: (1) successfully see or detect the presence of the animal; (2) determine whether or not the moose poses a threat requiring evasive action; (3) determine what action, if necessary, is required; and (4) implement the action. Whereas perception-reaction times of motorists have been studied in detail, allowing calculations of post-detection distances travelled by a vehicle at different speeds, distances to determine the distances at which an animal could be detected at night when it was positioned on each shoulder and in the middle of a highway using high and low beam headlamp settings of different vehicles. Overall, we found the mean detection distance across all vehicle types, headlamp settings, - tor; on the low beam setting, mean detection distance was 74 m and on the high beam setting it was 137 m. Moose decoy location was also important; combining the data for both headlamp settings, mean detection distances were 89 m, 93 m, and 133 m for the left, right, and centre positions, respectively. There was no relationship between headlamp height of different vehicles and moose detection distance. - nation capabilities of their headlamps for moose encounters. For drivers using a low beam headlamp ALCES VOL. 42: 75-87 (2006) Key words: Alces alces, detection distance, moose-vehicle collisions, MVCs, Ontario, visibility dis- tance Collisions between moose (Alces alces) and motor vehicles are a serious concern in many areas of North America and Fennoscan- dia (Grenier 1973, Child and Stuart 1987, Lavsund and Sandegren 1991, McDonald Bartley 1991, Child 1998, Joyce and Mahoney 2001, Lavsund et al. 2003, Seiler 2003, Tim- mermann and Rodgers 2005). At least 3,000 moose-vehicle collisions occur annually across North America (Child 1998); a highly conservative estimate since many accidents are not reported and most jurisdictions do not maintain accurate records (Child and Stuart 1987, Romin and Bissonette 1996, Sullivan and Messmer 2003, Transport Canada 2003). In northwestern Ontario alone, more than 400 moose-vehicle collisions were reported in 2002 (Staff Sergeant R. Beatty, Ontario Provincial Police, unpublished data 2004). - siderable numbers of moose and can result in substantial property damage, human injury, MOOSE DETECTION AT NIGHT – RODGERS AND ROBINS ALCES VOL. 42, 2006 76 and death; 20% of moose-vehicle collisions result in injuries with a 0.5% human fatality rate (Garrett and Conway 1999, Transport Canada 2003) and 26 human fatalities have resulted from collisions between vehicles and wildlife in northwestern Ontario over the last 10 years (Transport Canada 2003). The economic costs associated with moose- vehicle collisions include the material loss of vehicles, human injuries (ambulances, medi- cal expenses, disability payments), human fatalities (life insurance, funeral expenses), call-out costs for police, veterinarians, and moose, loss of meat and hunting opportunities, delays (Seiler 2003, Timmermann and Rodgers 2005); at an average cost of CDN$4,500 per accident, including only vehicle damage and loss of meat value (Transport Canada 2003), the economic cost of reported moose-vehicle collisions is at least CDN$13,500,000 annually in North America. Notwithstanding the potentially severe social and economic consequences of moose- vehicle collisions, these accidents can directly reduce moose population numbers locally or affect their productivity through alteration of sex and age ratios (Leopold 1933, Peterson 1955, Child 1998). In North America, moose mortalities resulting from collisions with ve- hicles correspond to about 4% of the annual allowable moose harvest, ranging from 0.3% in Manitoba to 196% (i.e., almost double the annual allowable harvest) in New Hampshire (Child 1998). Of 1,673 non-hunting moose mortalities recorded in northeastern Ontario over a 10-year period (1983-1991), 48% were attributed to motor-vehicle collisions; total incidental fatalities were almost double the combined losses to predation, subsistence (Child 1998). Clearly, there is good reason to consider the importance of moose-vehicle collisions in the development of sustainable moose population management programs and the setting of harvest objectives. Moreover, in areas where collisions with motor vehicles populations, additional management actions accidents. A wide range of measures to reduce moose-vehicle collisions have been applied in various jurisdictions, with greater or lesser degrees of success, including; public education programs (e.g., pamphlets, posters, bumper create high quality habitat in areas away from highway corridors, vegetation management to widen transportation routes and improve roadside visibility, adjustments of travel speed, improved lighting and signage, construction of physical structures (i.e., fencing, one-way mirrors and ultrasonic warning devices, ul- traviolet (UV) headlamps, and, more recently, development of intelligent transportation sys- tems (e.g., microwave radar, infrared images, imaging) (Child 1998, Forman et al. 2003, JHWF 2003, Transport Canada 2003, Timmer- mann and Rodgers 2005). Of these, properly maintained fencing appears to be the most effective, but is impractical for extensive use because of high installation and maintenance and Bartley 1991, Forman et al. 2003, JHWF 2003, Transport Canada 2003). Alternatively, a combination of vegetation management and 1991, Child 1998). However, management of vegetation may only provide temporary reductions in moose-vehicle collisions and if not maintained to limit the growth of early seral vegetation that may attract moose to highway corridors (Child 1998). Regulating vehicle speed, on the other hand, is inexpen- ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 77 sive to implement and maintain relative to other measures. Most moose-vehicle collisions occur be- tween 1800-0200 hrs on straight and relatively where visibility is limited by encroaching vegetation (Stuart 1984, Child et al. 1991, Del JHWF 2003). To avoid an accident, drivers must successfully: (1) detect the presence of a moose; (2) determine whether or not threat that will require an evasive response; (3) determine what action (e.g., steering or and (4) if necessary, implement the chosen action (Olson 1996, Olson and Farber 2003). Some amount of time will pass from when action is completed, during which the vehicle will cover some or all of the distance between the vehicle and the moose. How much of that distance will be traversed depends on: (1) the (2) how fast the vehicle is travelling; (3) how an evasive manoeuvre. Whereas perception- reaction time (Olson 1996, Olson and Farber 2003) and the time and distance required to given travel speed (Russell 1999) have been documented, no data are available pertaining to actual driver detection distances for moose at night. The intent of this study was to de- termine the distance at which a driver operat- the presence of a moose. We also attempted to ascertain whether or not detection distance was related to variation in headlamp heights of different vehicle types. This information was then used in comparisons with previously - ing data to estimate travel speeds that may be implemented along highway corridors to motor vehicles and moose. STUDY AREA The study was conducted on an 800 m straight and level section of Highway 527 Canada. The 2-lane segment of highway used in the tests was asphalt covered with oppos- and roadway edges demarcated by 3m-wide cuts through natural forest (primarily balsam poplar, Populus balsamifera, trembling as- pen, P. tremuloides, and white spruce, Picea glauca on the west side of the highway was cleared distance of about 7 m and on the east side to almost 20 m. The section of highway used was intersected by several game trails show- of use by moose, thereby providing a realistic setting for the study. A s m a l l c l e a r i n g ( N 4 8 º 3 3 ’ 4 6 ” , W89º08’08”) on the west side of Highway 800 m section of Highway 527, approximately Canada, used in determinations of moose detection distances on a highway at night. MOOSE DETECTION AT NIGHT – RODGERS AND ROBINS ALCES VOL. 42, 2006 78 test site, was used as a staging area for drivers from view of the test segment by an almost and rolling topography. METHODS Moose Surrogate As it would have been impractical to control the behaviour of a live moose for the purpose of this study, a decoy was employed bull moose decoy constructed from foam, real antlers. The moose-hide covering was critical in simulating the luminance properties of a moose at night. The moose surrogate was located about 600 m from the start of the test section of the highway, and just north of an existing natu- ral game trail. During the trials, the moose surrogate was set up on one of the shoulders or in the centre of the highway and always faced west. Drivers The test subjects in this study consisted of 14 drivers from the local geographic area who ranged in age from 20 to 55 yrs. The mean and median ages of the tested drivers were 38 and 40 yrs, respectively. Four subjects were female, 10 were male. Three subjects required no corrective eyewear while driving, 3 wore contact lenses, and 8 wore eyeglasses while driving. Vehicles and Headlamp Heights Seven vehicle types were used in this study (Table 1). The vehicles were chosen to - can highway motor vehicles and represented a variety of standard headlamp types and heights above ground (measured to the middle of the headlamp on each vehicle). The only common vehicle type not included in the test surface similar to that of a highway bus. The for proper alignment prior to the trials. Test Conditions At the time of the tests (2300-0430 hrs) with a quarter moon that set at about 0100 hrs. and the road was still damp in sections. As a result, when the air cooled through the night from +5ºC at the beginning of the trials to -4ºC at their conclusion, a sporadic low rolling fog condition was observed throughout the test area. The section of road near the moose surrogate target, however, was clear during all trials and the pavement was dry for most of the tests. During the tests, the highway was closed Vehicle type Year Model Headlamp type Headlamp height (cm) Motorcycle 2002 Yamaha V-Star 1100 Classic Sealed beam 87 Highway tractor 1998 International 90S Halogen 103 Minivan 2004 Dodge Caravan Halogen 74 Automobile (halogen) 2003 Ford Focus Halogen 65 Automobile (HID) 2004 Kia Amanti Xenon HID 71 2004 Ford F-150 Halogen 98 Sport utility vehicle 1995 Jeep Halogen 85 Table 1. Headlamp characteristics of test vehicles used in determinations of moose detection distances on a highway at night. ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 79 north of the test area. This allowed test vehicles to move safely at slow speeds and prevented any effects on visibility that might be caused Test Procedure In total, there were 42 test trials. Each driver was randomly assigned to a single vehicle (2 drivers per vehicle type) and to a single headlamp setting condition (high beam or low beam) for that vehicle, with the excep- tion of 4 subjects, who by virtue of requiring - cial tractor or motorcycle, were assigned to the appropriate vehicle type. Each of these 4 drivers, however, was assigned either the high beam or low beam condition on a random basis. Thus, each subject drove one of the test vehicles on either the high beam setting or the low beam setting, but not both. Each of the 14 subjects drove their assigned test vehicle 3 times, one for each moose location (left shoulder, centre of driving lane, and right shoulder). The order of the trials with respect to driver, vehicle type, and headlamp setting was randomly determined. to drive slowly through the test area using the assigned high beam or low beam headlamp setting until the moose surrogate was visually detected, then bring the vehicle to a full and immediate stop. One of the investigators ac- to ensure that the subjects were able to judge and maintain an approach speed of about 10-15 Once the vehicle was fully stopped, lumi- nance readings for the moose surrogate target the vehicle with a Hagner Universal Photom- eter Model S2 (B. Hagner AB, Solna, Sweden) capable of detecting light levels as low as 0-1 lux with an accuracy of ± 3%. However, in spite of the sensitivity of the photometer moose surrogate to the photometer placed at the front of the vehicle was so low (< 1 lux) that these measurements were abandoned after moose to the front surface of the vehicle was measured with a Laser Technology Impulse Laser Model 200XL (Laser Technology, Inc., Centennial, Colorado, USA) that can measure up to 2,200 m with a typical accuracy of ± 1 m and an accuracy of ± 2 m at the maximum distance. Following these measurements, the test subject turned the vehicle around and returned to the staging area. Statistical Analysis The dependent variable in this study, as the linear distance, to the nearest meter, between the moose target and the front surface of the vehicle at the point where the driver stopped the vehicle after visually detecting the presence of the moose surrogate on the highway. In addition to presenting the means (± SD) and medians (range) of these data from the trials, results are expressed in terms of the 15th percentiles to denote the visibility distances at which most drivers would be able to detect the presence of a moose on a highway under these test conditions. In this type of drivers within the 85th percentile, thereby excluding the 15% of tested subjects with the shortest detection distances for a particular set of conditions (Olson and Farber 2003). The study employed a 2 x 3 factorial design with repeated measures of detection distance independent variable was headlamp setting, for which 2 levels were established: high beam and low beam. The second independent variable was moose location, for which there were 3 levels: left side of the highway, centre of the driving lane, and right side of the highway. Each subject experienced all 3 moose location conditions, producing repeated measures on the moose location variable. Subsequently, a 2 x 3 factorial ANOVA (SPSS 13.0, SPSS Inc., MOOSE DETECTION AT NIGHT – RODGERS AND ROBINS ALCES VOL. 42, 2006 80 the detection distance data. Vehicle type was not directly analysed as a variable of interest because of limited confounded with other variables such as driver, type of headlamp system, etc. We were also unable to determine any relationships between detection distances and the types of headlamp systems (i.e., sealed beam vs halogen vs high intensity discharge) of different vehicles simple linear regression (SPSS 13.0, SPSS Inc., Chicago, Illinois, USA) was used to explore the relationship between detection distances and variation in headlamp heights among different vehicle types. Distances required to bring a vehicle to a safe stop from selected speeds were calculated data measured in previous studies (Russell 1999, Olson and Farber 2003). These required stopping distances were compared to fully adjusted detection distances of test drivers to determine whether or not there would be suf- a collision when travelling on a straight and Adjustment of Detection Distances for Test Drivers Before data obtained in this study could be used in comparisons with drivers in the real world, measured detection distances needed to be adjusted for the perception-reaction and stopping distances of the test drivers, as well as their expectancy of encountering the moose surrogate. From the time a driver detects the presence of an unexpected object-of-inter- est, to the time the driver is able to initiate some evasive response, perception-reaction will require about 0.50 – 1.25 secs for most (i.e., 85%) drivers (Olson and Farber 2003). react. Thus, the minimum perception-reac- tion time of 0.5 secs is appropriate for test subjects. Since the speed of the vehicle during or less, it would have travelled as much as to react to the moose surrogate and apply the (Russell 1999), an additional distance of vehicle to a comfortable but decisive stop from Accordingly, the measured detection distances were adjusted by adding 5 m to account for activities of test drivers. the test subjects in this study. Real drivers night-time visibility studies suggest an addi- tional 0.5 secs is a reasonable adjustment to the expected detection time for real drivers at night compared to experimental test driv- by drivers in the real world is subsequently calculated as a function of vehicle speed; e.g., would be 6.95 m closer to the moose surro- gate when it was detected than one of the test drivers. These distances were calculated for real drivers travelling at a range of different detection distances previously adjusted to account for the perception-reaction processes Calculation of Stopping Distances for Real Drivers Whereas a minimum perception-reac- ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 81 tion time of 0.5 secs may be suitable for test the highway at night, as above, a maximum perception-reaction time of 1.25 secs, as mea- sured in previous studies (Olson and Farber 2003), is more appropriate for most (i.e., 85%) real-world drivers. Thus, from the time that a moose is detected on a highway at night, it is expected that all but the 15% of drivers with the slowest perception-reaction times will be able to initiate an evasive manoeuvre within 1.25 secs. The distance travelled by a vehicle during the driver’s perception and reaction is speed dependent and is simply the arithmetic - tion-reaction time of 1.25 secs (Table 2). to a stop as the evasive action. Some other action such as steering, a speed reduction, or sounding a warning with the horn would complete stop, so our calculations account achieve an evasive response. The following directly incorporate the gravitational rate of complete stop from a particular speed: f S d 9.25 2 (1) where, d = distance required to stop (m); S f = deceleration rate and sliding on a well-travelled dry asphalt surface; Russell 1999), the distances required to bring the vehicle to a complete stop from selected speeds are given in Table 2. RESULTS Main effects on detection distance were found for both headlamp setting (F = 35.77; df = 1, 12; P = 0.00006) and moose location (F = 6.56; df = 2, 16; P = 0.008), but there was these two variables. Headlamp Setting The mean (± SD) and median (range) moose detection distances for the low beam headlamp setting were 74 m (± 29 m) and 75 m (23 – 124 m), respectively. The 15th percentile value was 47 m, indicating that most (85%) of the tested subjects were able to detect the presence of the moose from 47 m away or greater. The mean and median distances for the high beam headlamp condition were 137 m (± 51 m) and 147 m (28 – 210 m), respectively, with a 15th percentile value of 74 m. Moose Location The moose surrogate was set up at 3 locations on the highway. When data were combined for high and low beam headlamp conditions, the mean (± SD) and median (range) detection distances, respectively, for these moose locations were 89 m (± 55 m) and 64 m (23 – 189 m) for the left shoulder; 93 m (± 37 m) and 84 m (28 – 172 m) for the right shoulder; and 133 m (± 54 m) and 124 m (40 – 210 m) for the centre of the 50 60 70 80 90 100 110 120 Distance travelled (m) Perception-reaction 17 21 24 28 31 35 38 42 14 20 28 36 46 56 68 81 Table 2. Distances travelled by a vehicle during a driver’s perception-reaction time of 1.25 seconds MOOSE DETECTION AT NIGHT – RODGERS AND ROBINS ALCES VOL. 42, 2006 82 driving lane. The 15th percentile values for the 3 moose location conditions were 46 m, 73 m, and 79 m for the left, right, and centre positions, respectively. Vehicle Type and Headlamp Height There was no linear relationship between headlamp height of different vehicles and moose detection distance on either the low (r = 0.001; F = 0.000, df = 1, 19, P = 0.997) or high beam setting (r = 0.167; F = 0.543, df = 1, 19, P = 0.470). Nor was there any relationship between headlamp height and moose detection distance when the surrogate was located on the left (r = 0.018; F = 0.004, df = 1, 12, P = 0.951), right (r = 0.360; F = 1.783, df = 1, 12, P = 0.207), or centre (r = 0.014; F = 0.002, df = 1, 12, P = 0.962) of the driving lane. Total Data Set comparisons with required stopping distances, we combined the detection data across all vehicle types, headlamp settings, and moose location conditions, which produced mean and median detection distances of 105 m (± 52 m) and 99 m (23 – 210 m), respectively, with a 15th percentile value of 54 m. Adjusted Detection Distances for Test Drivers Although moose location was found distance, drivers in the real world obviously cannot predict or control the position of a live moose on a highway. On the other hand, real drivers can control the headlamp setting of their vehicle. Thus, adjustments were made to the 15th percentile detection distances of test drivers for the low and high beam headlamp setting conditions, as well as the total data set, for vehicles travelling at different speeds. As previously outlined, detection dis- account for the perception-reaction processes example, the 15th percentile value for moose detection distance in the total data set is in- creased to 59 m; for low beam and high beam settings, values are adjusted to 52 m and 79 m, respectively. Next, adjusted test values were reduced by the additional distance required for real world travelling at a particular speed; i.e., the distance travelled in an additional 0.5 secs at a given speed. Thus, for a vehicle travelling and the fully adjusted 15th percentile values were 45m for the low beam setting, 72 m for the high beam setting, and 52 m for the com- bined data set (Table 3). Fully adjusted moose detection distances estimated for real-world drivers travelling at other selected speeds are given in Table 3. For comparisons with fully adjusted detection distances of test drivers, distances travelled by a vehicle during a real-world driver’s estimated perception-reaction time (Table 2) to estimate the total distances re- quired, following detection of a moose, to bring a vehicle to a safe stop from selected speeds (Table 3). DISCUSSION When the distance required to perceive a moose on the road, react, and stop a vehicle exceeds the available detection distance at a given speed (Table 3), then a collision will above that speed, the greater the impact and potential consequences of a collision. Conversely, if the moose detection distance exceeds that required by a driver to perceive, react, and bring a vehicle to a safe stop from a given speed, then it is expected that a moose- vehicle collision can be avoided. Based on the setting, moose location, vehicle type, driver, etc.), the required stopping distance exceeds ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 83 or more (Table 3). Thus, drivers can avoid a moose-vehicle collision 85% of the time by at night. In most jurisdictions, however, it is recommended that drivers use the high beam headlamp setting on their vehicle when trav- elling on highways at night; e.g., in Ontario, drivers are expected to use the high beam headlamp setting at night whenever possible and switch to the low beam setting within 150 m of an oncoming vehicle or when follow- ing a vehicle within 60 m. In the high beam condition, the required detection distance to perceive, react, and stop a vehicle exceeds the available distance at speeds of 80-90 the required detection distance exceeds the available detection distance at speeds of 60-70 section of highway where the visibility trials is in agreement with the required detection distance on the high beam setting described in this study but too high for the low beam condition or combined data. Although moose location is unpredict- able in real-world situations, we found that visibility distance was affected by the loca- tion of the moose surrogate on the highway. Based on the 15th percentile values, the surrogate was detected further away when placed in the centre of the driving lane (79 m) or on the right shoulder (73 m), than on the left shoulder of the highway (46 m). This is consistent with Transport Canada (2001) regulations that ensure headlamps are aligned so the light does not project up or towards low beam setting; high beam headlamps are aimed so the brightest spot is centred at the same height as the headlamp. Thus, reduced detection distances when the moose surrogate was located on the left shoulder of the highway were largely the result of measurements made on the low beam headlamp setting. - lamp heights of different vehicles and moose detection distance, regardless of headlamp setting or the location of the moose surrogate headlamp alignment according to Transport Canada (2001) regulations. Although we ex- pected detection distance might increase with 50 60 70 80 90 100 110 120 Required distance (m) 31 41 52 64 77 91 106 123 Available distance (m) Low beam 45 44 42 41 39 38 37 35 (n = 21) High beam 72 71 69 68 66 65 64 62 (n = 21) Total 52 51 49 48 46 45 44 42 (n = 42) to a complete stop from selected speeds (sum of distances travelled during a perception-reaction 2) with distances available to complete the evasive manoeuvre based on moose detection distances expectancy, while travelling on a highway at night using low or high beam headlamp settings (n = number of trials). When the distance required exceeds the available detection distance at a given MOOSE DETECTION AT NIGHT – RODGERS AND ROBINS ALCES VOL. 42, 2006 84 height of the headlamps above the roadway surface, any potential improvement afforded to vehicle types with higher headlamps was negated by angling them downward to prevent low beam setting; this downward projection would also affect the aim of headlamps on the high beam setting. this study to real life depends on the degree to which the subjects, conditions, and procedures employed, correspond to those that would be expected in the real world. The vehicles used on Canadian roadways. The subjects were real drivers from the same geographic locale as the study and a real section of highway, which is normally frequented by moose, was used for the tests. The moose surrogate was conditions reproduced in the investigation procedures were as close an approximation to what a real driver would face, as would be possible in a study such as this. Nonetheless, there are a multitude of factors that might di- minish the ability of drivers in the real world to detect, perceive, react, and avoid colliding matter, on a highway at night. The drivers in this study lived in a region in which moose encounters are frequent and many of them had experienced moose encoun- ters on the roadway in the past. As such, this group of drivers, as a whole, could be consid- ered ideal. Many of these subjects were able to identify the presence of the surrogate moose target when only the lighter coloured lower legs were illuminated by the headlamps. An inexperienced motorist with regard to moose encounters might require additional detection time and therefore be closer to a moose upon completion of detection, leaving less room to Additionally, data collected in this study sober, alert, and unusually attentive drivers. A driver who is fatigued, momentarily dis- tracted by a passenger or in-vehicle device, or otherwise momentarily inattentive, would be expected to be closer to the moose at the point of detection than has been determined herein. These test trials involved a static target. The moose surrogate was placed on the road- way and “stood still” for each trial. Live moose are highly unpredictable and often in motion during encounters with vehicles; they can enter the roadway quite suddenly. Through their movement, the light leg colours, vulva moose may be easier for motorists to detect than the stationary moose surrogate used in these trials. While a moose in motion might provide additional visual cues that assist in would nonetheless face more complex and challenging avoidance situations in moose- vehicle encounters than did the test subjects in this investigation. The results of this study must also be considered preliminary because practical constraints restricted the variables examined to headlamp height, setting, and moose location. Vehicle types varied, but not systematically. numbers of subjects to permit independent, rather than repeated measures across the moose location variable. Ideally, sample unique detection distance summary data for headlamp illumination, moose location, vehicle type, and headlamp type conditions, since these characteristics are normally fairly moose-vehicle collision. Of course, these trials should be conducted under a variety of weather conditions at different times of the year and on various road surfaces. While luminance values were not a critical measure of interest in this study, it might be useful in the future to ALCES VOL. 42, 2006 RODGERS AND ROBINS - MOOSE DETECTION AT NIGHT 85 ascertain the luminance differences between the moose surrogate employed in this study and that expected from a live animal. It is possible that the sheen from a clean coat or the drab appearance of a wet and dirty coat of a live animal could present visual cues for real drivers that are different from those inherent in the decoy used in the present investigation. Follow-up investigations should also consider ways to test differences in detection distances for moose at night between stationary and moving targets. In the present endeavour the target remained stationary during each trial and only its location across the highway was varied. A moving moose might present a motorist with a different set of visual and cognitive challenges. MANAGEMENT IMPLICATIONS Our results (Table 3) suggest that most drivers travelling at speeds in excess of about to be overdriving the illumination capabilities of their headlamps for moose encounters. Even when the high beam headlamp setting is previous studies that have found an increase in moose-vehicle collisions when travel speed al. 2003). Thus, it would be prudent to suggest that along highway corridors where collisions with motor vehicles present a serious threat - pacts on local moose populations, speed limits Unfortunately, lowering speed limits is not generally favoured or supported by motorists or road authorities (Lavsund and Sandegren 1991). Speed limit signs do little to change driver behaviour and motorists travel at speeds determined by their perception of roadway - ed speed limits (Romin and Bissonette 1996, Putman 1997). Thus, it may be more accept- able to recommend diurnal or seasonal speed limit reductions (JHWF 2003). For example, approximately 70% of wildlife-vehicle colli- sions in northwestern Ontario occur between June and October (Staff Sergeant R. Beatty, Ontario Provincial Police, unpublished data 2004), suggesting a reduction of speed limits during that period. Both Texas and Montana appear to be too high, according to the present study, to effectively reduce wildlife-vehicle collisions, and only Montana has moose. Based on previous studies (Stuart 1984, For- man et al. 2003) and our results, it would be more reasonable to recommend speed limits of These recommended speeds will not prevent moose-vehicle collisions from occurring but incidents, particularly if combined with other for speeding through areas where collisions with motor vehicles present a serious threat may get a driver’s attention and remind them to slow down, automated radar speed detectors and public service announcements of where, when, and why speed reductions are being implemented (JHWF 2003). ACKNOWLEDGEMENTS of the Ontario Provincial Police, especially Staff Sergeant Bob Beatty and Rod Brown, and members of the Ministry of Transportation of Ontario, especially Tom Marinis, without - ing of this study would not have been possible. 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