Overtaking explained: Times when illegal passing moves are permitted

ROAD traffic rules such as the meaning of signs and markings and use of lanes are similar in the majority of countries, but some minor elements differ as we cross borders and, in practice, a lot of native or resident drivers in a given country may not be clear on a few aspects.

One of these is where overtaking – on single carriageways – is prohibited, and where the exceptions to these prohibitions are, so Spain's General Directorate of Traffic (DGT), part of the ministry of transport, has issued some guidelines.

When overtaking is not allowed

Overtaking on roads with one lane only in either direction is against the law on a bend or other elements that render visibility poor, or where the road surface changes – something that can often be the case on inter-provincial highways, especially where they cover more than one region, as investment in infrastructure repairs and maintenance in one province or region and lack of in another means a new spread of tarmac can abruptly stop at a border.

Also, overtaking is forbidden on marked pedestrian crossings, in intersections, at level crossings or close to them, and inside tunnels – except, in all cases, where the road is a dual carriageway or has three or more lanes.

In many cases, the ban on passing drivers in front is made visible with 'no overtaking' signs or by an unbroken white line down the middle of the road, but on smaller lanes these are not always in place, so motorists need to know when they are required to stay behind the car in front even if no indications tell them so.

Whilst most drivers are broadly aware of the above, and common sense kicks in where they are not sure, road traffic laws change relatively quickly – not exactly every couple of years, but certainly a handful of times since the average adult passed his or her driving test, after which they no longer have any mandatory instruction sessions or theory lessons to keep them up to date.

To this end, when many of today's motorists first got their licences, speed limits on national non-motorway highways were 100 kilometres per hour (62mph) as opposed to 90 kilometres per hour (56mph), town roads had a 50-kilometre (31mph) limit rather than 30 kilometres (18.6mph) and there were no specific rules about distance that should be left when passing vulnerable road users.

This means many may not be aware of those exceptions when the 'no overtaking' rule can, and even should, be discarded.

When 'forbidden' overtaking manoeuvres are allowed

According to the DGT, overtaking is permitted on an intersection where the driver passing has priority – this will be indicated via road markings.

Level crossings where lateral visibility is not an issue are another exception – for example, motorists are permitted to overtake a two-wheeled vehicle which does not impede the side view or that of a safe distance up ahead in the opposite lane.

Overtaking is permitted on roundabouts, except where these are intersections, provided 'the circumstances allow this manoeuvre to be effected safely', the DGT explains.

Drivers are required by law to leave a minimum gap of 1.5 metres (4'11”) between themselves and cyclists when passing these, even if this means having to cross an unbroken white line – in fact, if the way ahead is completely clear, it is better to cross the line to pass a cyclist rather than staying behind the bike until you reach a broken white line, which normally indicates that overtaking is permitted; having to slow to a crawl for some distance means traffic queues can build up behind you, which leads to frustration on the part of other drivers who may be tempted to overtake rashly and cause an accident.

On a stretch with a broken white line, though, overtaking a vehicle when there is not a safely clear and vehicle-free distance to do so in the opposite lane is illegal, and the same applies when overtaking cyclists: If you cannot leave a 1.5-metre gap because of cars streaming down the opposite lane, then you must stay behind until it is safe to pass.

The 'cyclist gap' is likely to increase to two metres (6'6”) later this year, but as yet, this has not been confirmed.

Horses being ridden on roads should be treated the same way as cyclists in this sense, and vehicles should slow right down when passing them – although horses are schooled to be safe in traffic and would not be exercised on a road if they were not, they are unpredictable and even the quietest animal can suddenly spook at an object by the roadside or a loud noise.

A common complaint among drivers slowing for horses is that 'the riders do not thank them' for doing so – but, firstly, a rider has to focus on his or her horse to ensure complete control in a potentially dangerous situation and cannot be expected to have one hand almost permanently off the reins to signal to a continuing stream of cars every few seconds; and secondly, slowing down for horses is a legal requirement, and drivers should not expect to be 'thanked' merely for not breaking the law – after all, they would not expect acknowledgement for stopping at a red traffic light or a zebra crossing.

Along the same lines, and again, as long as the way ahead is sufficiently clear, if the carriageway is blocked up ahead by a broken-down vehicle, in part or in full, you are allowed to cross an unbroken white line or 'ignore' a 'no overtaking' sign to get past it, even in a tunnel or on a level crossing.

This extends to passing exceptionally-slow vehicles – small motorcycles or mopeds, which typically travel well below the speed limit as they cannot go any faster; trailers carrying horses, which should keep to around 50 kilometres per hour for safety; horse-drawn carriages; or car-drivers who have inexplicably and dangerously slowed to a crawl on a fast-moving road, risking a serious rear-shunt incident, can be passed as long as the opposite lane is clear, even in a tunnel, level crossing, intersection or unbroken white line situation.

Generally, this applies to any obstruction in the carriageway.

The premise is that it is always safer for traffic to remain at a constant flow than for intermittent stops and slowdowns, which can cause a domino-effect pile-up if the car behind does not have time to react sufficiently.

For this reason, motorists should stick to the pace of the rest of the traffic, as long as it is safe to do so and the speed limit is respected – generally, one should drive at or just below the limit on a single-carriageway road unless it is dangerous to do so, such as in poor weather conditions; a 20% drop below the speed limit can be equally as hazardous as going above it, since vehicles moving much more slowly than the rest can lead to drivers behind becoming irritated and being tempted to overtake where it is perilous and illegal to do so.