Abstract Manager

The relationships between changing posted speed limits, motorists' driving speed, and collision frequencies are complex and intriguing. Much research has been conducted to explore the correlation between changing posted speed limits and the operating speed of vehicles, with varying conclusions. Additionally, researchers have attempted to establish a relationship between the operating speed of vehicles and collision frequency on different roadway types.

In Fall 2019, the Ministry of Transportation of Ontario launched a pilot program to raise the posted speed limit from 100 km/h to 110 km/h on three freeway sections in Ontario. Traffic information was collected before and after pilot implementation at the study and comparison sections including upstream and downstream of the pilot study sections where all attributes of the freeways are similar.  The primary difference between the study and comparison sections is the raised posted speed limit.

In March 2020, COVID-19 resulted in travel disruptions, creating a unique opportunity to examine the initial safety and operational impacts of raising freeway speed limits and the highway safety impacts associated with the COVID-19 response measures.

The main objectives of this paper are to: (1) quantify the impact of the raised speed limit on the operating speed of the study freeway sections; (2) quantify the safety impact of the raised speed limit on the study sections; (3) estimate the impact of reduced volumes due to COVID-19 restrictions on the operating speed of vehicles; and (4) evaluate the changes in collision frequency and severity along the study sections due to COVID-19 restrictions.

To address each objective of this paper, a separate before and after study with a comparison group was conducted. The 85^th percentile speeds along the pilot sections increased between 0 to 3 km/h after raising the speed limit. The average speeds remained unchanged and the speed limit compliance increased across all pilot sections by as much as 18%.

 A review of the post-implementation six-month period (a period associated with "normal" traffic operations) did not reveal any immediate safety issues related to the Pilot.  There were no observed significant changes in speeds or collisions compared with previous years.  Post COVID-19, it was found that the Pilot locations experienced a greater reduction in all collision types relative to the control locations and to all Ontario freeways during the first two years.  This paper will provide a more fulsome discussion of the data collected and analyzed during this time.