A fire engine needs 9ft (2.7m) clearance to pass safely. Streets congested with parked cars can delay fire engines and other emergency service vehicles attending an incident.
Firefighters say they have had difficulty accessing Dove Street in Stewkley.
Watch Manager Bob Stilton, from White Watch at Bletchley Fire Station, said: "We are urging residents to think about their parking as they could be putting the lives of their families, friends and neighbours at risk.
"Inconsiderate parking can mean the difference between the emergency services saving a life or not. Cars may be able to pass down streets which have restricted access due to double parking or incorrect parking, but fire engines and ambulances can't."
Buckinghamshire Fire & Rescue Service's Community Safety Team, backed by Thames Valley Police and South Central Ambulance Service, has produced a leaflet to help stations to tackle the problem.
Firefighters will attach leaflets, in clear plastic pouches, to any vehicles which cause them a problem.
Road safety manager Keith Wheeler said: "Many streets were not designed to accommodate the number of cars that residents want to park in them. This leaflet will help stations try to tackle the problem of inappropriate parking in their local streets.
"This will also support the work of many Neighbourhood Action Groups who have highlighted parking problems as an issue of local concern."