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How risky is driving on the other side of the road? What the data actually shows

Research summary · Last updated 7 August 2026

Plenty of travellers wonder whether renting a car in a country that drives on the opposite side is genuinely riskier, or just feels that way. The research says it is genuinely riskier — but not in the way most people expect. Here is what the studies and official crash statistics show, with sources.

The short answer

Drivers switching to the unfamiliar side of the road do crash more often, and research on tourist road safety repeatedly identifies driving on the unfamiliar side as one of the most common causes of traffic accidents involving tourists. The elevated risk is largest in rental cars, and the crashes are not caused by recklessness. They happen at low-attention moments — pulling out of a car park, turning at a quiet junction, joining an empty road — when there is no traffic to copy and old habits take over.

The clearest study: opposite-side visitors in Greece

The most direct evidence comes from a peer-reviewed study on the island of Crete (Petridou et al., 1997, Accident Analysis & Prevention). Greece drives on the right. As summarised in a later peer-reviewed review of foreign-driver accident risk (Yannis et al., 2007, Journal of Safety Research), the study found that visiting drivers from left-side driving countries (such as the UK, Ireland, Australia and Japan) had a markedly higher road accident risk than visitors from right-side countries — and the risk was highest when they were driving a rented car rather than one they owned.

That is the side-switch effect isolated about as cleanly as crash data allows: same roads, same conditions, same tourist status. The one thing that differed was which side of the road the driver's habits were built for.

A follow-up study on Corfu (Petridou et al., 1999) looked at the problem from the hospital end: among local residents and Greek tourists, around 15% of all recorded accidents were traffic-related. Among foreign tourists, the figure was 40%.

Governments count these crashes as their own category

This is not only an academic finding. Several countries with left-side traffic formally record wrong-side driving by visitors as a crash cause.

Scotland. Transport Scotland records collisions caused by "inexperience of driving on the left" as an official contributory factor. In 2023 it recorded 35 such collisions, up 46% on the previous year, including one fatality. Most visitors to Scotland come from mainland Europe and the United States — right-side countries — and road safety campaigners have called for more reminder signage on rural routes as a result.

Ireland. Wrong-side driving by visitors has been a recognised problem for decades. A 2003 analysis reported in the Irish Times found driving on the wrong side was a contributory cause in 16.3% of the crashes examined, and the US Embassy's own advice to American visitors has warned that tourists driving on the wrong side cause several serious accidents in Ireland each year. Kerry County Council went as far as passing an emergency motion to install extra signs and road markings after a cluster of wrong-side incidents near Killarney.

If national transport agencies maintain a crash category for it and county councils hold emergency votes about it, the hazard is real.

It is not reckless driving — it is habit

An Australian research programme run ahead of the Sydney 2000 Olympics analysed every reported crash involving an international driver in Queensland over six years (Watson, Wilks et al., 1999, Australian Transport Safety Bureau). Australia drives on the left, so most of its international visitors arrive with right-side habits.

The findings are the interesting part. Crashes involving overseas drivers were less likely than local crashes to involve alcohol or speeding. Instead, the researchers pointed to fatigue and disorientation in unfamiliar surroundings, and noted this was particularly relevant for drivers from right-side driving countries. An earlier Australian government monograph had already flagged the same pattern (Federal Office of Road Safety, Driving in Unfamiliar Surroundings, Part 1: International Drivers, 1995).

In other words: the tourists who crash are mostly careful, sober, experienced drivers. Their reflexes are simply calibrated for the other side of the road. And reflexes do the driving precisely when attention is lowest — the first turn out of the rental lot, the quiet junction, the empty roundabout with no car in front to follow.

An honest note about the New Zealand numbers

New Zealand publishes some of the world's best data on visiting drivers, and it is often quoted carelessly, so it is worth handling properly.

NZ Transport Agency figures show that over 2012–2016 about 6.2% of fatal and injury crashes involved an overseas driver, and that a share of at-fault overseas drivers "failed to adjust to New Zealand rules or conditions". The agency is also careful to note that overseas drivers are a small share of the total road toll and that these crashes have stayed relatively constant or declined.

The nationality breakdowns in the NZ data need particular care. The countries most often listed — Australia and the UK among them — largely reflect who visits New Zealand in the greatest numbers, and Australian and British drivers already drive on the left. So raw nationality counts from New Zealand do not, by themselves, demonstrate a side-switch effect. The cleaner evidence for that is the Greek study above (where the sides can be compared directly), the Scottish "inexperience of driving on the left" category, and the Queensland finding that disorientation was concentrated among drivers from right-side countries.

We would rather present the data accurately than dramatically. The accurate version is still clear: switching sides is a specific, documented crash risk, concentrated in rental cars and in the quiet moments where habit, not attention, is steering.

What travellers can actually do about it

The encouraging part of the research is that the risk is narrow. It is not "tourists are bad drivers". It is a short list of habit traps:

Habits can be retrained, and retraining before the trip beats improvising at the first roundabout. The first 30 minutes after pickup is where that preparation pays off most — and the awkwardness usually fades within a day or two.

MirrorLane is a familiarisation tool, not driving instruction. Real signs, road markings and local rules always come first.

Sources

Frequently asked questions

Is driving on the other side of the road actually more dangerous?

The research says yes, but specifically rather than dramatically: studies of tourist crashes repeatedly identify driving on the unfamiliar side as a common cause, with the risk concentrated in rental cars and at low-attention moments. It is not reckless driving — careful, sober, experienced drivers crash because their reflexes are calibrated for the other side.

When are side-switch crashes most likely to happen?

At low-attention moments when there is no other traffic to copy — pulling out of a car park, turning at a quiet junction, or joining an empty road. That is when old habits, rather than conscious attention, do the steering.

How can you reduce the risk before a trip?

The risk comes down to a short list of habit traps: which way to look first, which lane to finish a turn in, joining empty roads, roundabouts that flow the other way, and adjusting to a mirrored car. These are habits you can retrain before you travel rather than improvising on arrival.