Details:

Creators:
Valdes, Didier ; Colucci, B.
Valdes, Didier ; Colucci, B. Less -
Corporate Creators:
Safety Research Using Simulation (SAFER-SIM) University Transportation Center
Subject/TRT Terms:
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Behavior Driving Simulators Evaluation High Occupancy Toll Lanes Periods Of The Day Speed Limits Traffic Congestion Traffic Lanes Traffic Safety Transportation Facility Operations Width
Resource Type:
Tech Report
Geographical Coverage:
Puerto Rico
Corporate Publisher:
Safety Research Using Simulation (SAFER-SIM) University Transportation Center
Abstract:
The Puerto Rico Dynamic Toll Lane (DTL) is a 6.44 mi (10.4 km) reversible facility within a stretch of freeway PR-22 that operates a congestion pricing system; the first of its kind in the Commonwealth of Puerto Rico. This managed lane system is shared by private vehicles and the Bus Rapid Transit (BRT) system and is located at the median of PR-22, between the freeway lanes. However, the DTL has conflict/decision points at the entrance, as well as in the diverging lanes before the bridge piers segment, during the bridge segment and after the bridge separation, and in the exits of the DTL, for both eastbound and westbound directions. This has generated safety concerns for administrators and road users as well.

This research project presents the study of the PR-22 DTL using the UPRM driving simulator, which is located in the Transportation Laboratory of the University of Puerto Rico at Mayaguez (UPRM). The main goal of this research was to evaluate the DTL facility’s safety and driver behavior on this system. In order to complete this goal, a Full Factorial Design of 33 was used. Three factors of interest were selected at three levels, where each level represented a treatment, namely, lane width (i.e. 12, 11 and 10 feet), posted speed limit (i.e. 65, 55 and 45 mph), and time of day (i.e. morning, evening, and night). A total of 27 scenarios were developed for this designed experiment that used a block design to replicate the base scenarios between three representative groups. To evaluate the performance of subject drivers and the road safety associated with the DTL, three dependent variables were used as a surrogate measure, namely, average speed, acceleration noise and standard deviation of roadway position (SDRP). Moreover, these performance measures were evaluated in five zones of interest.

The results from the analysis of variance realized for this research project indicates that lane width variable had a statistical difference in all zones for average speed, whereas narrow lanes resulted in a reduction of average speed. Likewise, the time of day negatively affected the acceleration noise of drivers, increasing the variations of acceleration in Zones 2, 3, 4 and 5. As a result of this increment, a higher crash frequency inside the DTL can be expected. Furthermore, for the SDRP variable the result indicated that significant differences were found between the morning and night and morning and evening, before and after the bridge piers separation (Zone 2 and 4). Additionally, subject drivers used the incorrect DTL exit lane in approximately 26% of all simulated scenarios, with the 57% of them happening in the morning scenarios.

In conclusion, this research study provides the first-ever freeway safety evaluation of a managed lane system that combines reversible lane operations with a congestion pricing system in a highway facility that is shared by private vehicles and a Bus Rapid Transit (BRT) system. The statistical analysis indicated that the optimum scenario for the average speed in PR-22 DTL is a posted speed limit of 55 mph with 11 ft lane width. However, further research is needed to provide feasible countermeasures that improve road safety and efficient operations of the reversible DTL in both the short and long term.


Format:
PDF
Alternate URL:
http://safersim.nads-sc.uiowa.edu/final_reports/UPR-1-Y2_FinalReport.pdf
Collection(s):
US Transportation Collection University Transportation Centers
Main Document Checksum:
[+]
urn:sha256:b4ffdab29a1e7f9b5c673763315f8d5309ecf764b54d58e0c424a8c0f142f49a
Download URL:
https://rosap.ntl.bts.gov/view/dot/31891/dot_31891_DS1.pdf
File Type:

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