(2001, Robert De Niro, Edward Burns, Kelsey Grammer)

Steve Bunce notes: “A thriller starring Robert de Niro as a New York cop. A street chase about half an hour in shows good views of a Bristol VR semi-open topper. The bus is halted and the camera moves around the bus at various angles. Others who know these vehicles may be able to ID.”
There are a couple of early views of RTS transit buses, the first with the faintest hint of a Bristol VRT semi opentopper in the distance. It's likely the RTS in these caps is the same bus seen twice; it's an ex Orange County GMC RTS Mk IV new in 1980 and provided for the movie by Regional Transit Service in whose fleet it carried fleet number 3037:

A Bristol VRTSL3 semi open topper with Grayline New York is glimpsed during the chase:

My guess is this is the same bus (D228) that appears almost immediately after. Note the conversion of the bus to a single offside (from a UK perspective) centre entrance door, also that the bus is described as a 68 seater, rather than the 74 seat capacity it was originally built with. D228 was new in 1977 in the UK as West Riding 789 (XWU338S):