Watch Top Gear Season 21 Episode 4 Online

William Woollard looks at ways to mitigate traffic congestion, while Jeremy Clarkson examines some of the competing solutions to London’s problems and comes to a novel conclusion. Off-road motorcycle rallies have given rise to a new breed of commercial bikes. Chris Goffey assesses their leisure use off the road, and their practicality in towns. The AC Cobra still evokes a special excitement among enthusiasts. Beki Adam reviews this marriage of a big American V8 engine and a sophisticated British sporting chassis. Tiff Needell tests two Grand Prix Karts — 250cc machines capable of 150 mph.