Door Width Rule

Door Width Rule

One of the four Defensive Driving rules is the 'Door Width Rule'. All drivers must maintain safe space at the sides of their vehicle using the 'Door Width Rule' and its proportionate multiples depending upon their speed when passing parked cars and other stationary objects.

 

The Door Width Rule states that : 

"When travelling at 50 km/h (30 mph) never become closer than a door's width, i.e. 1 metre (3 feet) when passing a parked vehicle, to allow for the possibility of a door opening".

Wherever there is less space due to hazards on both sides of your vehicle, speed must be reduced in proportion.

When travelling at higher speeds, a greater width of safety margin must be maintained.

Whenever passing cyclists or pedestrians, double (at least) all the minimum safety margins, or (at least) halve your speed.

  

 

minimum space available

maximum safe speed

metric

0.2

metre

10

km/h

0.5

metre

25

km/h

1

metre

50

km/h

2

metres

100

km/h

imperial

1

foot

10

mph

2

feet

20

mph

3

feet

30

mph

6

feet

60

mph

 

Defensive Driving demands that we must always maintain a safety zone around our vehicle. The 2-Second Rule, the Diagonal Rule, the Queueing Distance Rule, and this Door Width Rule all show us that 'Space is your friend, no-one ever crashed into a space'. Very simply, if you do not become close to another road user or object it is impossible to have a collision. You must always intend to have at least 1 metre (3 feet) of space on all 4 sides of your vehicle, and often much more.

 

However, if the sides of your vehicle have to become closer than 1 metre (3 feet) to another object, you must slow down.

To maintain safe space at the sides of your vehicle use this simple formula: for every 200 millimetres of space never exceed 10 km/h (for every foot of space never exceed 10 mph). This may sometimes seem slow, but it is necessary to in order to maintain safety. Always consider other hazards that may suddenly appear, e.g. persons moving into the road from behind a parked vehicle; always consider what you can't yet see - it's what you can't yet see that will surprise you most.

 

When you pass any other road-user you should aim to have 2 metres (6 feet) of clearance between the side of your vehicle and the road user, especially when overtaking cyclists and motorcycles and when pedestrians are walking on the edge of the road.

 

You should also attempt to maintain at least 1 metre (3 feet) between your vehicle and any fixed object e.g. lamp posts, trees, railings, bridge parapets.

 

It is very important that you have a 1 metre (3 feet) safety zone when you pass any parked vehicle as that is the width of an open door, if the driver or a rear passenger should open the door just as you are passing you will be able to miss it.

 

However, it is also important that you do not become too close to oncoming traffic on the other side of your vehicle, so there are many reasons why you may need to slow down and use the "Door Width Rule".

 

 

© Keith Lane B.Sc. 2009