Around 1/3 of crashes involving provisional drivers are caused by choosing gaps that are too small and result in collision.
Guidelines, not rules
The advice here are not hard and fast rules but guidelines to help as you build your gap selection skills.
What is a safe gap?
Safe gap = turning, overtaking, changing lanes, and crossing intersections without endangering road users or causing collision. No one should need evasive action (changing lanes or heavy braking).
Key points summary
- Safe gap = turning, overtaking, changing lanes, and crossing intersections without:
- Impacting the crash avoidance space of other vehicles
- Making others take evasive action
- If the gap is not large enough, wait
Guidelines for safe gap selection
Safe gaps vary with the speed of the traffic and road and weather conditions.
Selecting safe gaps when turning
A key hazard perception skill is selecting a gap for you to safely complete the turn. This is often difficult, as you need to watch for road users to the front, left and right.
Safe gaps – turning left
Left turns are sharper than right turns and may take longer. You also need time to accelerate to match the speed of the traffic (higher speed = more time).
Assuming a 60km/h zone and traffic is actually travelling at 60km/h:
This 6-second gap needs to be a judgment, as you can’t count it out when you need to make the turn. The 6-second gap will be the same for different speeds, but the distance won’t be. At 60km/h it’s roughly 100m and at 80km/h the gap increases to 135m. This is a guideline and it’s important to develop these skills when driving.
Key points summary
- When turning left in a 60km/h zone you need a 6 second (100m) gap to your right
- If the gap is not large enough, wait
Safe gaps – turning right
Right turns are more complicated than left turns because you need to look for road users in multiple directions.
Features of right turns
Right turns require you to cover more road but are generally less sharp than left turns meaning you can accelerate quickly to match the speed of the traffic.
Guidelines for right turns
Assuming a 60km/h zone and traffic is actually travelling at 60km/h:
You will quickly clear the traffic from the right, hence the smaller gap. You need time to complete the turn (3 seconds) and accelerate to the speed of traffic (3 seconds) on the far side of the road, hence the 6-second gap to the left.
Turning right at a cross intersection
Turning right at an intersection with 4 directions is harder as you must look 3 ways to judge a safe gap. You need:
- 4 second gap to the right
- 6 second gap to the left
- 4 second gap to oncoming vehicles
Practice these more complex situations when you have built confidence with simpler gap selections.
Turning right at traffic lights
This is simpler than uncontrolled intersections as you only need to look for a gap in oncoming traffic. However, many provisional drivers pick gaps that are too small or misjudge the speed of traffic. Assuming a 60km/h zone and traffic is actually travelling at 60km/h you need a 4-second (70m) gap to oncoming vehicles.
Key points summary
- When turning right in a 60km/h zone you need a:
- 6 second (100m) gap to your left
- 4 second (70m) gap to your right
- 4 second (70m) gap to oncoming traffic
- If the gap is not large enough, wait
Safe gaps – Making U-turns
U-turns fall just outside the 5 most common crash types. U-turns are more difficult than right turns. You must look for traffic approaching from behind and in front.
Features of U-turns
U-turns are sharper than right turns and require more road to complete. U-turns are tight turns often from a stationary position. Generally, you can’t accelerate until you have completed the turn and require a large gap to get up to the speed of traffic.
A word of caution
U-turns are dangerous and should be avoided unless necessary. A better option is to turn into a side street, do a three-point turn and rejoin traffic in the right direction.
Key points summary
- If it is dangerous to do a U-turn, so don’t. Do a three-point turn in a side street
Safe gaps when crossing intersections
Features of crossing intersections
It takes at least 3 seconds to cross a standard two-way road. When crossing an intersection in a 60km/h zone you need a:
- 3 second (50m) gap to your right
- 4 second (70m) gap to your left
You may need less if you don’t come to a complete stop but if in doubt, stop when you’re sure you have a safe gap.
A median strip may allow you to cross the intersection in two stages. Select a safe gap to the right and move to the middle of the road. Complete the crossing when there is a safe gap to the left.
Key points summary
- When crossing an intersection in a 60km/h zone you need a:
- 3 second (50m) gap to your right
- 4 second (70m) gap to your left
- If the gap is not large enough, wait
Safe gaps when overtaking
Head-on collisions are often severe as the speed of the two vehicles combines (e.g. two 60km/h cars colliding = one 120km/h car hitting a stationary object). When overtaking you need enough space to avoid colliding with the vehicle you’re overtaking and oncoming traffic. It is similar to passing vehicles on highways but more dangerous as you must cross the centre line into oncoming traffic.
A word of caution
Overtaking is usually done to maintain your speed, though the decision is your own. The best thing to remember is not to overtake unless you have to (e.g. to pass stationary or broken down vehicles).
Features of overtaking
It is difficult to accurately judge if the gap you take is large enough to safely overtake a vehicle. Overtaking is particularly hazardous when your view of oncoming traffic is blocked (e.g. by a truck or bus). Choosing a safe gap and executing the manoeuvre safely is difficult and many provisional drivers have little experience.
Guidelines for selecting safe gaps for overtaking
When overtaking you must account for:
- Traffic conditions
- The size of the vehicle you want to overtake (larger vehicles like semi-trailers or road trains (up to 5 and 9 times longer than a car respectively) take longer to overtake)
- The acceleration capacity of your vehicle (less capacity = longer overtake time. Plus a car’s ability to accelerate is reduced at higher speeds)
You should start practice on multi-lane roads so you can learn what a safe overtaking gap looks like. If you don’t feel confident about overtaking, don’t do it.
Key points summary
- A safe overtaking gap is your overtaking time plus a safety margin of at least 3 seconds
- If it doesn’t look or feel safe to overtake, then wait until it is safe
Do not exceed the speed limit to overtake. Whenever possible, you should wait for regular overtaking lanes (signposted in advance) to overtake slow traffic.
Continue reading the Hazard Perception Handbook Summary:
2. Crash Patterns of Provisional Drivers
4. Keeping Space From Other Vehicles
5. Selecting Safe Gaps
Check out the other resources available to help you pass the Hazard Perception Test so you can take the Practical Driving Test:
L Plates (Learners)
Red P Plates (P1)
Green P Plates (P2)
Full Licence