Dr. Cody S. Stolle
Date of this Version
The purpose of this research is to design, evaluate, and simulate passive safety devices for passive safety control. Simulations were conducted in CarSim to determine if passive safety devices, such as chicanes and speed tables, would allow non-threat vehicles to pass safely through an access control point (ACP) but adversely affect threat vehicles.
Chicanes are beneficial by forcing vehicles traveling in an ACP to navigate around a series of barriers which are spaced apart at distances determined by a selected design speed. Vehicle performance limits evaluations were conducted by using a calibrated vehicle model in CarSim, which used steering, driver control, engine model, and system control features. Simulation results determined that existing guidelines were not conservative for roads narrower than 40 ft and design speeds greater than 30 mph, but were conservative for wider roads and lower design speeds. Therefore, researchers recommended full-scale testing to validate findings for the UNL proposed chicane designs.
On the Phase I study, it was discovered that vehicles can be launched off of the top of the speed table at high speeds. Simulation studies were conducted to determine an optimized speed table shape that achieved comfort for non-threat vehicles but launched threat vehicles. Two speed tables were recommended: (1) a 10-ft approach slope with a 10-ft table top and (2) an 8-ft approach slope with a 10-ft table top. Then, researchers evaluated vehicle traversals over speed tables placed on curves with varying radii to evaluate how threat vehicle paths could interact with the speed tables. For radii between 100 and 1,000 ft, vehicles traveling at the maximum stable cornering speed were significantly disrupted by the speed table. However, further analysis indicated that threat vehicles may be able to modify behaviors and mitigate consequences of speed tables placed on curves. Additional study is recommended to determine suitable placement of speed tables.
Researchers recommend further investigation on consecutive speed tables on curves and alternative threat vehicles, which may provide more conservative results on chicanes designs.
Advisor: Cody Stolle