During 1951 and 1952 Mercedes-Benz produced the 170 D OTP version of the W136 170V for police use only. Apart of a couple of differences in the materials used on the basic structure of the car, the 170D OTP was delivered with technical and body features that were not offered on other models including -and for the first time- a truck accessible from the outside. As a requirement, all the cars should be painted in "Police Green", but in the end most of the cars delivered to the police were painted blue. This four door cabriolet was also fitted with Mercedes´M136 1.7L inline 4 engine, paired to a four speed synchromesh manual transmission.