Overall, Canada has excellent road infrastructure. The TransCanada Highway is the longest national highway in the world; it is almost 8,000 kilometres (5,000 miles) in length.
All of the major roads in Canada are paved. People drive on the right side of the road in all provinces and territories. Speed limits are posted on the sides of the road. Generally, highway (freeway) speeds are limited to 100 kilometres/hour, and rural highways are usually limited to speeds of 80 kilometres/hour. Main city roads may have a limit of 60 km/h, and smaller roads usually have a speed limit of 40 km/h.
Most people, if they have a driver's license and access to a car, could and would drive to their destination in less than a day if it were less than 600 kilometres away. Driving on main highways with speed limits of 100 km/h, 600 kilometres would about a six-hour drive.
No one quite knows why, but many Canadians think in terms of time instead of distance. For example, if you ask "How far is it from Toronto to Montréal?", the answer will often be "About five hours," instead of "About 500 kilometres."
Many people drive their cars to and from work during the work week. Traffic during the morning and evening "rush hour", usually between 7 and 9 in the morning and 5 and 7 in the evening, can be quite congested; it can take upwards of an hour to get to or from work. Most large cities in Canada are surrounded by suburbs - these are large urban areas where people live. Many people who live in the suburbs work in the downtown area; when most people begin work between 7 and 9 in the morning, the roads in from the suburbs can get very busy.
To conserve gas, money and wear and tear on their cars, many people carpool to and from work. This means that a small group of people drive in the same car, and the passengers pay the driver an agreed-upon amount for gas.
Gas in Canada is sold by the litre. (One US gallon is 3.8 litres.) In the last few years, prices have usually varied between 0.66 and 0.77 per litre, but recently, prices have gone as high as $1.00 per litre in BC, and over 0.90/litre in Ontario and Québec.
People like to joke that there are only two seasons in Canada: winter and construction. Because of the cold temperatures in the winter, spring through fall is when road work and other construction is done. The CAA (Canadian Automobile Association) has links to each province and territory's highway conditions: http://www.caa.ca/e/travel/highway.shtml.