Length of a vehicle affects A. width of traffic lanes B. extra width of pavement and minimum turning radius C. width of shoulders and parking facilities D. clearance to be provided under structures such as overbridges, under-bridges etc.

The correct answer is: D. clearance to be provided under structures such as overbridges, under-bridges etc.

The length of a vehicle affects the clearance that needs to be provided under structures such as overbridges, under-bridges, etc. This is because the vehicle needs to be able to pass through these structures without hitting the top or bottom. The clearance required is typically based on the length of the longest vehicle that is expected to use the structure.

The other options are not directly affected by the length of a vehicle. The width of traffic lanes is typically based on the number of lanes and the type of vehicles that are expected to use the road. The extra width of pavement and minimum turning radius are typically based on the turning radius of the largest vehicle that is expected to use the road. The width of shoulders and parking facilities is typically based on the number of vehicles that are expected to use the shoulder or parking lot.