In 2009 Gorski Consulting created this roadway grid to explore the speeds and positioning of vehicles passing through a sharp curve.

Governments spend money to post various warning signs on highways but do drivers heed these warnings? It would seem to be a waste of money if these signs were ignored. Gorski Consulting has conducted testing that reveals some interesting results.

In 2009 Gorski Consulting conducted a series of videotaping sessions on a challenging S-curve of Clarke Road in the north-east of the City of London, Ontario. The figure shown above is taken from testing conducted on October 8, 2009. This figure shows how a grid of markers was set up on the pavement in the curve so that vehicle speeds and their position within the lane of the curve could be documented. At that time a speed advisory sign had been posted advising motorists that they should proceed through the curve at a speed of 60 km/h, as shown below.

In October of 2009 a speed advisory sign warned drivers that they should proceed through the S-curve of Clarke Road at a speed of 60 km/h.

Ten years later, in late September, 2019, the speed advisory sign was changed to lower the advised speed to 50 km/h, as shown in the figure below.

Would drivers take this advised speed reduction into account and lower their speeds?

An analysis of the average speed of vehicles passing through this curve was conducted based on the videotaping from 2009. Based on 70 northbound vehicles whose speeds were documented using multiple video camera technology the average speed was 75.2 km/h. 31.4 percent of these vehicles were found to be travelling at a speed of 80 km/h or higher. Thus 31.4 percent of drivers were travelling at 20 km/h or higher than the advised speed. Out of the 70 vehicles that were documented not a single driver was observed to be travelling at a speed of 60 km/h or less.

What sense is there to install these warning signs? Transportation officials in Ontario conduct similar speed documentations to what has been done by Gorski Consulting. Thus they are fully aware of these statistics.

Further multiple video camera documentation was conducted at this site in the autumn of 2019, or ten years after the results noted above. This documentation was completed a few weeks after the lowered advised speed was posted. This video is in the process of being analysed and the results will be made available shortly. What do you think the results will show?