It's a gas, gas, gas

Ford wants to diffuse exhaust gases so cars in convoy don’t create such a
stink for each other. It warns that when one vehicle is 5 metres behind another,
the noxious exhaust fumes from the rear-facing exhaust nozzle are diluted by
only 50:1, whereas pedestrians at the roadside are breathing a dilution of 500:1
or higher. Ford’s new exhaust (GB 2 344 853) will bend 90° into a perforated
tube that extends across the rear of the vehicle. The holes point down, and are
shielded by baffles which spread the fumes. This improves the air for cars
behind.…