How do potholes form and what is the City of Ottawa doing about them?

The weather we've experienced in Ottawa this winter season (2013-2014) has been challenging - and not just in Ottawa, but across Canada. Since November 1, 2013 the City of Ottawa has received more than 230 cm of snow and experienced significantly colder temperatures than normal for a longer period than usual. Overall, the temperature has been below average with freeze/thaw cycles also occurring later in the season than normal. This has led to an increase in the volume and severity of potholes, as frost penetrated deeper into the ground and will take longer to rise out as it warms up.

Generally, potholes are formed when water seeps into cracks in the surface of the road which, combined with the vibration of traffic over those cracks, causes the asphalt to fail. Potholes are also created when the roadway is stressed by trucks and buses as this can cause movement of the subsurface. Once there is a weak spot, every car that travels over the area increases the depth, and, eventually, a section of the material will fail causing a pothole to form.

Current Status

The Public Works Department takes a proactive approach to maintaining potholes year round. In addition, this year there has been a substantial increase in the number of pothole service requests generated by the public. You can report a pothole by calling 3-1-1 (613-580-2400) and providing the following information: The street name and number or street name and intersection closest to where the pothole is located. Additionally, the City produced a short video about potholes and how to report them. This is shared with the public via OttCity Online.

Pothole repairs began a little earlier than usual this year - on January 13, 2014. This was caused primarily by the thaw/ freeze that occurred in late December and again in early and mid-January. Since then, crews have been repairing potholes when weather conditions are favourable. Typically, snow events are the only time that pothole repair crews are not deployed.

Number of potholes repaired and number of service requests received

Year (January 1-March 18) Number of Potholes Repaired Number of 3-1-1 Service Requests for Potholes
2014 56,075 3,330
2013 57,797 2,770
2012 43,546 1,466

Data as of March 28, 2014

In order to improve response to pothole repairs, the Public Works Department is undertaking the following initiatives:

  • Sourcing additional contracted crews to be hired on a temporary basis; currently the Department deploys 5 contracted crews. The number of new crews will depend on availability.
  • Experimenting with different types of cold patch, including one that is said to have extra bonding power.
  • Researching different products and asphalt mixes as well as best practices in order to improve operations for future years.
  • Adding 9 new hotboxes. These can be utilized with existing staff.
  • Sourcing a used grinder (smaller and mobile) for immediate purchase. This will enable staff to make more permanent repairs to the chronic pothole areas by cutting out a larger area that can be properly compacted by a roller.

The Public Works Department will continue to provide the highest level of service possible in order to address potholes throughout the year. In the meantime, please continue to report any potholes you find in your travels online through ServiceOttawa or call 3-1-1 (613-580-2400).

Why does Ottawa get so many potholes in the winter?

The City of Ottawa posted an explanation for residents about the freeze-thaw cycle that leads to potholes all over the City. Here it is, along with a video that gives residents a better idea of how crews patch these holes during the winter months:

With freeze-thaw weather cycles comes the deterioration of road surfaces and potholes.

During the thaw, the water gets down in the crevices of the road. When the freeze returns, the water expands – popping out asphalt and increasing the size of the holes, especially when vehicles drive over them.

We met with the City’s asphalt crew to learn more about how potholes are formed and how they work to repair them.

The City’s crews do their best to respond to reports of potholes. It’s a big job and last year alone 193,000 were filled.

If you spot a pothole, you can help immediately by:

  • Calling 3-1-1, 613-580-2400 (TTY: 613-580-2401)

We appreciate your help with reporting potholes to ServiceOttawa or 3-1-1 (613-580-2400) - and so will everyone who shares the road with you!