The MP for Sittingbourne and Sheppey has called for improved safety measures on the Sheppey Crossing, which was the scene of a 150-car pile-up in September 2013.
Gordon Henderson wants the Highways Agency to improve the A249 bridge urgently.
Dozens of people were hurt in last year’s multiple crash, which happened in thick fog.
Police are also compiling a report on a crash that killed a woman and her son on the crossing in July this year.
Mr Henderson told the House of Commons: “What I do not understand is why a review of safety cannot be undertaken on last year’s series of crashes.
“I am increasingly concerned about the length of time the investigation is taking by the police and I am worried about what might happen while the Highways Agency waits for their report.”
In a statement to the BBC, the Highways Agency said: “Safety is one of our top priorities. We regularly carry out our own internal reviews, and following any incidents where the police carry out an investigation and make recommendations, we naturally take full account of any of those recommendations.”