New increases to Ontario highway speed limits could put people — and the planet — at risk, a McMaster expert warns.

The province rolled out increased speed limits of 110 km/h on select sections of highways, following a two-year pilot program.

“These evidence-based increases are a common-sense change to make life more convenient for Ontario drivers while bringing our highway speed limits in line with other Canadian provinces,” Transportation Minister Prabmeet Sarkaria said in April, when he announced the changes.

But the increases don’t consider driving habits and put drivers at risk, says Mohamed Hussein, an associate professor in the department of Civil Engineering.

 “I can say with 100 per cent confidence that increasing the speed limit will increase the number of fatal collisions on the road,” Hussein says.

We spoke with him about his concerns.

What are your thoughts on the speed limit increase?  

Most people believe that they can drive at faster speed limits with no problems. But when you increase your speed, you are putting yourself at an elevated risk of collision.

When you drive at a higher speed, no matter how good of a driver you think you are, you will need a longer distance to stop if you need to, and you are increasing the probability of skidding while taking evasive action or negotiating a curve.

The risk increase is very small, but all it takes is just one mistake for this small risk to turn into a disaster.

We’ve heard people say: people drive faster than the speed limit anyway, so it won’t make much of a difference. 

The average speed on our highways is already a number between 110 and 120 km/h. The first argument everyone thinks about when supporting the speed limit increase is that people speed anyway, so it makes sense to increase the speed limit, which will reduce speed variability and improve safety.

What is wrong with this argument is that it naively assumes that people will comply with the new speed limit.

In fact, exceeding posted speed limits is a “daily routine” practised by many drivers. A study conducted in Australia showed that only 9 per cent of motorists followed the speed limit and, on average, drivers exceeded the posted speed limit by about 10 per cent.

Drivers’ speed choice is influenced by several factors, including enforcement efforts, weather conditions, road geometry, the purpose of travel, and the behaviour of other drivers on the road, but most importantly, it is influenced by the posted speed itself.

If we increase the speed limit, many drivers will automatically drive faster than the new speed limit and the average speed will always be higher than the posted speed.

What do you think is the motivation behind the increase?  

Increasing the speed limit is a political decision. When the Ministry of Transportation (MTO) surveyed residents to get their feedback about increasing speed limits on freeways, 80 per cent of Ontarians supported the idea, according to MTO. With this huge support, it is very tempting for any politician to adopt such a policy.

People think we’ll see improved mobility and reduced speed variability between drivers. Improved mobility means reducing travel time, mainly.

In my view, this is not entirely true: If you commute from Mississauga to McMaster, which is roughly 50 kilometres, and you are driving on an empty road, which rarely happens, you will save 5 minutes by driving 20 km/h faster.

Most people drive at times when highways are operating close to capacity. Numerous studies show that we will not gain any mobility benefits by increasing the speed limit in these conditions.

Reducing speed variability is a plus for sure — but keep in mind that we will not eliminate variability, we will only reduce it.

The benefits we may get from reducing the speed variability do not compensate for the downsides.

What are the downsides here?  

I can say with 100 per cent confidence that increasing the speed limit will increase the number of fatal collisions on the road.

We may argue about the total number of collisions — some studies concluded that the total number of collisions will increase if we increase the speed limit, and some do not support this.

But what all studies agree on is that the number of fatal collisions and the number of people killed on the road will increase.

A collision happening at a speed higher than 120 km/h will most likely be fatal. So if we increase the speed limit, at best we will maintain the number of collisions that we currently have, but the consequences will be worse (i.e., the number of people who die or are severely injured because of the collisions).

This is confirmed almost everywhere in the world. There is a famous study from the University of British Columbia in 2016 that assessed B.C.’s decision to increase the speed limit on some highways. The study showed an 11 per cent increase in fatal collisions after increasing the speed limit, after controlling for all variables.

As a professional engineer, I won’t support a policy that I know for sure results in more deaths on the roads (even if it is one person) for a minor convenience for the rest of the drivers.

Increasing speed limits will also have negative impacts on the environment. The transportation sector is one of the major contributors to greenhouse gas emissions and climate change. Increasing speed is associated with higher energy consumption, higher emissions, and higher noise levels.

The example that everyone likes to use when arguing for speed limits is the German Autobahn (which has several sections with no speed limit at all). In September 2022, the European Transport Safety Council issued a warning on rising German road deaths and recommended imposing a speed limit on the Autobahn.

In 2023, a study published in the Journal of Ecological Economics showed that Germany could save 950 billion a year by imposing a 130 km/h speed limit on the Autobahn. The study considered the value of time, fuel consumption, infrastructure, crashes, carbon dioxide emissions, and air pollution.