Ronin is notable for a number of car chases, the last being a particularly lengthy one through the streets and tunnels of Paris; some scenes used up to 300 stunt drivers according to the DVD director commentary. Car work has been a specialty of Frankenheimer, a former amateur racing driver, ever since his 1966 film Grand Prix.
Although action sequences are often shot by a second unit director, Frankenheimer did all these himself, and sometimes rode along. While he was aware of the many innovations in digital special effects since then, he elected to film all these sequences live, to obtain the maximum level of authenticity. To further this, many of the high-speed shots have the actual actors in the cars. Skipp Sudduth did nearly all of his own driving, while other cars were right hand drive models with stunt drivers driving - crashes were handled by a stuntman. To lend additional authenticity, the sound recordist re-recorded many of the vehicles in the chases to ensure that during the editing, the right sounds were dubbed in for each vehicle.
Several cars are used in the chases, including an Audi S8 D2, a Peugeot 406, three Peugeot 605s, a Citroën XM, a BMW M5 E34 and Mercedes-Benz 450SEL 6.9, a rare Mercedes-Benz W116 variant with a high-powered engine, as noted by Frankenheimer in the DVD. Most famously, a 1998 Audi S8 quattro, portrayed as stolen to order and then fitted with a nitrous oxide power-booster, is chosen for its bulk, grip and torque and driven in Paris and Nice by Sudduth's character. As a result, the car was rated 9th in Car magazine's Top 40 Coolest Movie Cars. The Frankenheimer DVD commentary indicates that the cars were towed through the streets of France at high speed, not simulated, by a Mercedes-Benz 500E.
Jean-Claude Lagniez, the car stunt coordinator, supervised approximately 150 stunt drivers for various sequences in Ronin. They drove at speeds up to 120 miles per hour (190 km/h), and 80 cars were intentionally wrecked during the course of the production.
The final scene at the Zénith de Paris had 2,000 extras, according to Frankenheimer.