Key Takeaways
- The middle lane is not a default cruising lane — keeping left when clear is required by law.
- Merging traffic does not automatically have right of way; both drivers share responsibility for a safe join.
- Following distance should increase at higher speeds, not stay fixed at a car length or two.
- Hazard lights do not substitute for proper signalling or excuse stopping on a live carriageway.
- Speed limits on motorways are a legal ceiling, not a mandatory minimum or a guaranteed safe speed.
Why Motorway Myths Are Particularly Dangerous
Misconceptions about driving are common, but those specifically about motorways carry outsized risk. At high speeds, small errors in judgment — rooted in bad information — can escalate rapidly. New drivers often arrive on their first motorway having absorbed a mixture of half-truths from passengers, online forums, and informal advice that contradicts what the Highway Code actually says.
Getting these facts straight isn't about passing a test. It's about building the kind of confident, accurate mental model that keeps you — and everyone around you — safer. See our guide for new licence holders for a broader look at the mindset behind safe driving from day one.
Myth
The middle lane is the safest place to cruise on a motorway — it gives you options on both sides.
Fact
Drivers should keep left and only use outer lanes for overtaking. Middle-lane hogging is a traffic offence in the UK.
The belief that sitting in the middle lane is a cautious choice is one of the most widespread motorway myths. In practice, it reduces overall capacity, forces other drivers to undertake or over-take unnecessarily, and creates friction. The Highway Code (Rule 264) is clear: keep left unless overtaking. Returning to the left lane after overtaking is not optional — it is required. Middle-lane hogging can result in a fixed penalty notice and points on your licence.
Myth
Traffic joining from a slip road has right of way and motorway drivers must move over for them.
Fact
Merging drivers must give way to traffic already on the motorway, though courtesy and situational awareness benefit everyone.
This myth likely originates from confusion with roundabout rules or a misremembered version of 'zipper merging.' On a motorway, drivers joining from a slip road are responsible for matching speed and finding a safe gap — they do not have automatic priority. That said, Highway Code Rule 259 encourages drivers already on the motorway to adjust their position or speed where it is safe to do so, helping traffic flow. Responsibility is shared, but the joining driver carries the primary obligation. See also: how merges and junctions catch drivers out.
Myth
Hazard lights warn other drivers effectively, so it's fine to use them when slowing suddenly in traffic.
Fact
Hazard lights can mask your indicators and confuse other drivers; their use while moving is restricted and situational.
Some drivers activate hazard lights during heavy braking or in slow-moving queues, believing it adds a warning. While some countries permit or encourage this, in the UK the Highway Code specifies that hazard lights should be used when stationary to warn that your vehicle is temporarily obstructing traffic — not as a substitute for brake lights or indicators while moving. Using hazards while driving can prevent following drivers from reading your intentions at a junction or lane change.
Myth
You can drive right up to the speed limit in any conditions — it's legal, so it must be safe.
Fact
Speed limits are a legal maximum, not a target. Wet, foggy, or congested conditions often demand considerably lower speeds.
Legislation sets speed limits as a ceiling under ideal conditions; it does not define what is appropriate for the road state at any given moment. Stopping distances roughly double on wet roads compared to dry. In fog, spray, or at night, the gap between 'legal' and 'safe' widens substantially. Driving at 70 mph in poor visibility may be lawful but can still constitute dangerous driving if it results in a collision. Speed should always be adjusted to conditions, not anchored to the posted sign.
Myth
If you stay two car lengths behind the vehicle ahead, your following distance is always sufficient.
Fact
Following distance should be calculated in time, not car lengths. At motorway speeds, two seconds is the minimum in ideal conditions.
Two car lengths sounds specific, but its meaning changes entirely with speed. At 30 mph it represents about 2.5 seconds of gap; at 70 mph it shrinks to under one second — far less than the human reaction time of roughly 1.5 seconds before braking even begins. The standard guidance is a minimum two-second gap in dry conditions, measured by a fixed point. In rain, that should extend to four seconds or more. The metric is time, not distance.
Myth
Undertaking — passing a slower vehicle on its left — is always illegal on a motorway.
Fact
Undertaking is generally discouraged and can be dangerous, but it is not always illegal; the rules are more nuanced.
The Highway Code advises drivers not to overtake on the left and to avoid undertaking, but the specific prohibition applies most clearly when it requires moving to a lane on the left to pass. In slow-moving queued traffic where the left lane is moving faster than the right, it is not always an offence to travel faster in the left lane. However, deliberately weaving left to pass vehicles is dangerous and may constitute careless driving. The key distinction is whether your lane happened to move faster, versus deliberately maneuvering left to undertake.
Speed, Distance, and the Margins That Matter
Two of the most dangerous motorway myths relate to speed and following distance — areas where overconfidence has measurable consequences. The posted speed limit tells you the legal maximum; it says nothing about the appropriate speed for wet roads, reduced visibility, or heavy traffic. Understanding the difference between a legal limit and a genuinely safe speed is one of the most important steps any driver can take.
Following distance compounds this. At 70 mph, your vehicle covers roughly 31 metres per second. The two-second rule is widely misapplied, and in adverse conditions it should be extended significantly. Relying on a fixed number of car lengths — rather than time-based spacing — is a myth that leaves no margin for human reaction time.
31 m/s
Distance covered per second at 70 mph
At motorway speed limits, a vehicle travels approximately 31 metres every second, illustrating why following distance must be measured in time, not car lengths.
2×
Increase in stopping distance on wet roads
The UK Highway Code notes that stopping distances approximately double on wet roads compared to dry conditions at equivalent speeds.
Road layout also changes what safe driving looks like. How your technique should adapt across different road types is worth understanding before you encounter those conditions for the first time.
This article provides general driving information and education. Always refer to the current Highway Code and consult a qualified driving instructor for guidance specific to your situation and jurisdiction.