id	keyword
american_scientific_journal-6510	road
american_scientific_journal-6510	traffic
american_scientific_journal-6510	research
american_scientific_journal-6510	level
american_scientific_journal-6510	design
american_scientific_journal-6510	safety
american_scientific_journal-6510	maintenance
american_scientific_journal-6510	network
american_scientific_journal-6510	study
american_scientific_journal-6510	speed
american_scientific_journal-6510	criteria
american_scientific_journal-6510	upgrading
american_scientific_journal-6510	evaluation
american_scientific_journal-6510	engineering
american_scientific_journal-6510	section