Cancellara, who briefly got stalled by the crash, sighed with relief: "I'm really happy to get past that, a fall early hurts ... today it was calm, and then hectic at the finish."
David Moncoutie and Anthony Delaplace of France and Japan's Yukiya Arashiro broke away early and chiseled out a maximum lead of 8:40 at mile 10, but the pack reeled them in with about six miles left in the stage.
Riders set off from Abbeville — a town where 6,000 buildings were destroyed or damaged in a German bombing raid in World War II in May 1940 — and rode along the English Channel's picturesque, chalky cliffs with views of giant wind-turbine installations.
Thursday's fifth stage promises another bunch sprint, after a mostly flat 122-mile course from Rouen to Saint-Quentin north of Paris.
AP Sports Writer Samuel Petrequin and Associated Press writer Greg Keller in Rouen, France, contributed to this report.
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