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TRID: The TRIS and ITRD Database


The knowledge of drivers on who has the right-of-way between the one on mainline lanes of a freeway and the one entering the freeway through on-ramp junction lane was evaluated. In addition, drivers’ opinions on how to make the on-ramp junctions safer were collected. A survey instrument with 21 items requesting drivers’ information in regard with demographics, freeway driving experience, knowledge of right-of-way and merging practices was used for data collection. The results show that crashes are relatively rare events and for some reasons, most of them never happen but result into near misses, which can not be reported and documented. Most drivers act correctly when driving on freeway mainlines when they see a vehicle trying to merge from an entrance ramp but act improperly when merging into freeways from on-ramp lanes. Some drivers cannot identify which driver has the right-of-way at the merge area between the mainline and the on-ramp drivers. Yielding problems due to bad drivers’ attitudes have been identified by drivers as the leading cause of freeway-ramp merge area crashes, followed by lack of attention and drivers entering the freeway at low speeds. Most of the drivers believe that they need longer acceleration lanes, better ramp signing and better driver’s education especially in terms of sign meaning and entrance ramp safety in order to make freeway-ramp merge areas safer. Due to sampling problems encountered in this study, one has to be careful when interpreting these results because the sample completely missed teenage drivers and over-sampled older drivers.

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Document available for download is the authors' accepted manuscript, provided with the permission of author Deogratias Eustace. Permission documentation is on file.


Crash data, Crash records, Crash reports, Driver experience, Human factors in crashes, Mainline metering, Merging traffic, On ramps, Right of way (Traffic), Traffic regulations