Traffic associated

• School opening times arranged to avoid peak hour traffic (in some countries, private car school pickup and drop-off traffic are substantial percentages of peak hour traffic)[citation needed]

• driving behaviour promotion and enforcement. Driving practices such as tailgating and frequent lane changes can reduce a road's capacity and exacerbate jams. In some countries signs are placed on highways to raise awareness, while others have introduced legislation against inconsiderate driving.

• Visual barriers to prevent drivers from slowing down out of curiosity (often called "rubbernecking" in the United States). This often includes accidents, with traffic slowing down even on roadsides physically separated from the crash location. This also tends to occur at construction sites, which is why some countries have introduced rules that motorway construction has to occur behind visual barrier

• Speed limit reductions, as practiced on the M25 motorway in London. With lower speeds allowing cars to drive closer together, this increases the capacity of a road. Note that this measure is only effective if the interval between cars is reduced, not the distance itself. Low intervals are generally only safe at low speeds.

• Lane splitting/filtering, where space-efficient vehicles, usually motorcycles and scooters, ride or drive in the space between cars, buses, and trucks. This is however illegal in many countries, being perceived as a safety risk.