Cars are mostly 1d vehicles in practice, unless they are bumper cars. We try really hard to minimize 2d interactions between cars by stacking multiple 1d enviro

Cars are mostly 1d vehicles in practice, unless they are bumper cars. We try really hard to minimize 2d interactions between cars by stacking multiple 1d environments (lanes) and ignoring the 2nd dimension for the most part. Where we cannot ignore it we try to make it safe by adding turn lanes, roundabouts, traffic lights or building interchanges.