Safety impacts of signal-warning flashers and speed control at high-speed signalized intersections

摘要: For many years, to reduce the crash frequency and severity at high-speed signalized intersections, warning flashers have been used alert drivers of potential traffic-signal changes. Recently, more aggressive countermeasures such intersections include a speed-limit reduction in addition flashers. While speed-control strategies further improve crash-mitigation effectiveness flashers, rigorous statistical analysis data from has not undertaken date. This paper uses 10-year 28 Nebraska (all with intersection approaches having signal-warning flashers; some no reduction, others either 5 mi/h or 10 speed limit) estimate random parameters negative binomial model nested logit crash-injury severity. The estimation findings show that, while wide variety factors significantly influence crashes, effect is ambiguous—decreasing crashes on increasing it others, decreasing severities others. In contrast, limit unambiguously decreased both injury-severity crashes. It speculated presence potentially heterogeneous driver responses limits, smaller distances covered during reaction time lower speeds (allowing higher likelihood avoidance) reduced energy associated limits are necessarily sufficient decrease when just mi/h. However, they Based this research, reductions conjunction appear be an effective safety countermeasure, but only clearly so if least