Home About ATSIP Program Awards Venue Sponsors/Exhibitors

Implementation of Vehicle Activated Advance Stop Warning Signs


Abstract:  Each year, hundreds of crashes occur due to a driver failing to notice a stop-controlled intersection and driving through without stopping. In the Selwyn District of New Zealand, this problem is particularly prevalent due to flat, straight roads which intersect regularly across the district. Between 2011 and 2015, New Zealand Police (NZP) in the Selwyn District recorded 47 crashes specifically attributed to drivers who did not stop at a priority-controlled intersection. These crashes resulted in three fatalities, four serious injuries and 27 minor injuries.

 A major issue noted by NZP were drivers failing to notice a stop sign and driving through an intersection at the open road speed limit. To counter this issue, a new intelligent solar-powered Advanced Stop Warning Sign (ASWS) has been developed and trialed in the Selwyn District. ASWSs are activated by radar when a vehicle approaches an intersection on a leg controlled by a stop sign. The signs are located 200m in advance of the intersection and are activated when a vehicle is approximately 150 to 200m from this point. The signs have high intensity LEDs and a strobe type pulse that alternates between two lights. These flashing lights draw drivers’ attention towards the sign to make them aware and alert of the approaching intersection.

A trial of this technology was deployed at three intersections in the Selwyn District in 2016. Since the trial commenced there have been no injury crashes at these sites involving a driver failing to notice a stop sign. These highly encouraging results provided the impetus to identify other intersections in New Zealand where ASWSs could be an effective countermeasure for improving rural intersection safety performance. While crash data in New Zealand is of high quality, it is not possible to determine from coded crash data alone where drivers fail to notice an intersection. To address this, hand-written Traffic Crash Reports (TCRs) were analyzed from the Selwyn District to inform the development of an automated crash analysis algorithm that could be used to identify intersections with ‘fail-to-stop’ type crashes. When applied to the Selwyn District, the automated crash analysis algorithm correctly identified all intersections that had at least two crashes which may have been preventable using an ASWS. This algorithm was applied to national crash data to identify the 50 highest ranked intersections where an ASWS could be an effective safety intervention. Detailed analysis showed more than 200 ‘fail-to-stop’ crashes had occurred at these intersections, of which 80 caused injury and 45 resulted in fatalities or serious injuries. A national program to deploy ASWSs at these high-risk locations is underway. ASWS are low-cost treatments that deliver highly effective outcomes when installed in the right locations. They have the potential to significantly improve safety outcomes at rural intersections globally where ‘fail-to-stop’ crashes are prevalent.

Carl O'Neil - Co-authored presentation with New Zealand Police Sergeant Dan Harker. Carl is a Senior Transportation Engineer at Abley Transportation Consultants. He has a Bachelor of Engineering degree from the University of Canterbury in New Zealand with First Class Honors in Civil Engineering. Carl has a strong analytical background and has particular expertise in the integration of data manipulation and GIS technologies to solve transportation and logistics problems. He has applied these skills to an ever-growing number of safety projects in New Zealand and Australia, bridging the gap between emerging analytical and technological methods and road safety applications.



Session Material
Quick Links


Chris Osbourn


fb_logo   linkedin