A more thorough explanation:

Vehicular means related to vehicles.

• There was heavy vehicular traffic on the highway during rush hour.
• The city council is discussing ways to improve vehicular access to the downtown area.

These examples show how the word "vehicular" is used to describe things that are related to vehicles. In the first example, "vehicular traffic" refers to the cars and trucks that are using the highway. In the second example, "vehicular access" refers to the ability of vehicles to enter and move around the downtown area.