Failing to get to an emergency on time has been blamed on bad weather conditions by Bucks and MK Fire Authority.
The year-end target for arriving in 10 minutes was 80 per cent, but there was just a 77.4 per cent success rate.
There was a 99 per cent year-end target to reach emergencies within 20 minutes, but it fell to 97.2 per cent.
There has also been a rise in the number of people killed and seriously injured in road traffic collisions with an increase of 88.
The report highlights the size of MK’s road safety team has been “steadily reduced”.
The figures have been revealed in a performance monitoring report by BMKFA, which will be discussed at the executive committee on July 30.