Is it safer to drive up or down a dangerous mountain road?

Usually driving down a steep hill with narrow turns is more dangerous down than up for the simple reason that gravity will accelerate you going downhill.

Going up hill gravity slows you down and your engine needs to work to overcome that which usually means that you're not driving fast enough to lose control, although the condition of the road may still play a part in putting you in danger.

You can take a look at several guides relating to downhill driving for steep hills including the list below:

• http://travel.thefuntimesguide.com/2005/07/downhilldriving.php
• http://www.letstalkdriving.co.uk/STEEP%20HILLS.htm
• http://www.roadtripamerica.com/tips/mountaindriving.htm

But if you're a visual sort of person:

• Ice Road Truckers

While it doesn't explain everything it gives a fairly decent guide to the dangers.

Pick the side that hugs you closest to the interior.

No matter if it zig-zags or has switchbacks, take a look at it and stick to the inside. In Australia, this may mean taking the route that hugs the left side. In Oman, this always meant the route that hugged the right side.

Ultimately the mountain road is equally safe either direction. The difference would be your driving skills, those of the other drivers on the road at the same time and the current road surface condition (wet, icy, dry).

If you are comfortable and practiced with driving mountain roads, then either direction is about the same. If you are inexperienced, then generally up hill is less stressful.

But you also have to take into consideration the terrain on both sides of the road, as going uphill on side of the road that sits a top a sheer cliff would be much more stressful than coming down the other side against the mountainside.

Your scenario of a truck careening downhill is equally dangerous to both directions, as it just just as easy take you out with a rear end collision as a head on one.

Bottom line, it depends on your driving skills.

Tom's mountain driving "rules of thumb" ... Use your transmission to control your speed, not your brakes ... Come down the steep grade in one gear lower than you went up (assuming up and down are similar grades ;-) ... Slow down before you enter the curve ...

I think the relative risk depends on the road, the traffic, your skill as a driver, and other conditions.

If it's a relatively empty road (very low traffic), then going up is probably safer, as the only risk you're facing is your own inability to navigate the road, versus the downhill risk of burning out your breaks and losing control of the vehicle due to mechanical failure.

But consider the other extreme: Very heavy traffic, large vehicles, in a region where safety practices are not well enforced. In such a scenario, going uphill may be more dangerous, as the odds of being hit head-on by an out-of-control truck may outweigh the risk of losing control yourself while going down hill.

Other factors which are likely to change the equation:

• 2-lane road or 4-lane road (or some other configuration)
• Is it a divided highway?
• Is the road icy? Wet?
• Is it windy?
• Is the road in good repair?

In summary, I expect the only truly useful way to answer this question would be to look at statistics for the particular road you're considering driving. Unfortunately, while statistics are often kept for specific segments of roads or certain intersections, I'm not aware of any agencies which track accident rates based on the traffic direction (divided highways being a likely exception to this).

I am a terrible driver and can have mishaps at the drop of a hat. For the scenario you have described, I would consult the navigator and attempt to infer the route that has the most traffic. This route would be preferable to me because with lots of traffic one can get 'inside' a group of cars somewhere near the end. This would be my strategy if the road conditions are poor, uphill/downhill makes no difference.

Trucks and lorries that careen out of control would most likely take out those at the front of the group. And for visibility, you are better off with a string of tail lights in front of you so you can minimally stay on the road and be alerted to something when the 'group leaders' apply the brakes.

Most importantly, when something bad happens, there will be other drivers who (in Europe) are required to stop and give aid.

For you're asking for 'actual accident data', I can contribute some personal experiences. I was run off the road three times on the continent, one of them dangerously so.

The road to Mount Athos is basically flat until you reach the last city, Ouranopouli, and then it is full on treacherous. There are just narrow and twisty dirt roads with lots of 'thrilling' hairpins. In my case I was driving uphill and got run off by a lorry going downhill who was coming out of a hairpin. This was about 2AM, rainy, foggy, and all-around horrible conditions. The problem with Mount Athos is you don't get the choice of roads, the border has one drivable road leading to it and then you have to park and hike in. Drive in the day time. Optimally get behind a big lorry and follow them in/out until you're past the nature park. There's a good reason people prefer to take the ferry!

Another time on the Route Napoleon I got run off voluntarily by a group of motorcyclists who were passing me on a hairpin. Essentially I got spooked and pulled over to avoid any sort of accident caused by on coming traffic. I am an erstwhile guide on the Route Napoleon, but will never undertake it between September and May. In the summer there are lots of motorcycle clubs who converge on the route because of the 'thrills' it offers: no guard rails, mountainous roads, horrifying stone arches at the head of hairpin curves, and gorgeous scenery to die for. Again, leave Cannes early on a clear day, like 9 or 10AM and plan to arrive in Grenoble that afternoon or stop along the way well before dusk.

And another time on a twisty road outside of Bayreuth. Again this was voluntary because there wasn't enough room for me and the lorry approaching. No collision and no permanent damage, but jarring nonetheless.

See also: Britain's most dangerous roads (I will not even think about driving on these).

So to square the circle, the answer to your question which direction is safer, uphill or downhill; my answer is they are both equally safe/dangerous.

I always was told "What goes up must come down"

There have been valid points made for both directions.. here's my take on it for WHEN you lose control

Losing control while traveling downhill, you can release your brakes and work on regaining control Losing control while traveling uphill, you come to a stop.. at least at first, if the road is REALLY bad, you'll start sliding downhill, and you won't have a chance to even steer.

My advice? GOOD WINTER TIRES.. no all-season crap, studs are a good idea, but cable chains will get you through some pretty nasty stuff too