What roads are safer - highway or surface?

A discussion on an email list had me thinking that as scary as the interstate highways can be, there are overall more accidents on “surface” streets.

Then, I realized I have no clue whether that’s true.

Does anyone have any cites for accidents / injuries / fatalities per passenger-mile or per car-mile for the various types of roads?

My WAG is that it’s like being in an airplane: overall you’re safer on the highways (in the airplane) but if something does go wrong, you’re more likely to die.

Check out page 70, Table 31, Percent of Fatal Crashes (by land use and speed limit); also Table 30, page 69, crashes by speed limit, crash type, and severity.

The greatest percentage of crashes were in the 35-40 mph range, while the most fatal crashes occured at 55 mph.

Part of these statistics are going to be affected by the fact that most of the time, most cars are not going 55 mph but something slower. I’m not sure these tables answer your question but maybe they are helpful.

from: http://www.fhwa.dot.gov/interstate/faq.htm#question16
Are the Interstates really safer?
One of the primary reasons for building the Interstate System was to improve the safety of the highway users: drivers, passengers, and pedestrians. Over the past 50 years, the Interstate System has done much to make highway travel safer and more efficient. Relative safety is measured by the “fatality rate” (fatalities per 100 million miles traveled, a measure used so data can be compared as traffic volumes change). The Interstate System is the safest road system in the country, with a fatality rate of 0.8—compared with 1.46 for all roads in 2004.
When the Interstate Construction Program began in 1956, the national fatality rate was 6.05. This improvement in safety has been the result of many factors working together: the shifting of traffic onto the safer Interstate highways and technological advances in safety, such as wider shoulders; slid-resistant pavements; better guardrail, sign, and markings; clearer sight distances; and breakaway sign posts and utility poles. In addition, many other factors have contributed to improved safety on the Nation’s highway system, including new vehicle safety features, such as shatter proof glass, padded interiors, safety belts and air bags; programs to reduce impaired driving; and the combined, coordinated efforts of many private organizations and public agencies working together to make the Nation’s highways ever safer.

More detailed numbers. Rural Interstates fatality rates are 47% that of other rural roads and Urban Interstates are 59% of other urban roads.


This subject was covered in some detail in the BBC stats programme More or Less (I couldn’t find a link to the exact episode, but it’s well worth listening to IMO).

They were tackling the subject of whether cycling is actually more dangerous than driving. And one of the factors they brought up was the fact that cyclists have to stick to back roads, whereas most driving is done on freeways (which is indeed much safer). So that will skew the statistics in favour of driving.

I’m curious - can you explain why you perceive them as scary?

Well, they don’t particularly terrify me; I drive the DC Beltway frequently and have gotten pretty used to it. I have a healthy respect for it though.

There are a lot of nutso people driving on the highways, things happen pretty fast, sudden slowdowns/lane changes etc., and a lot of different things happening from all directions, often quite unexpected - and at highway speeds (posted 55, real 70+) there’s not a lot of time to react to surprises.

Not to mention on some of the roads, there’s no place to go if you have a problem (there are highways here with no shoulder at all, and if you break down in a middle lane, no way to get there even if it exists)… needless to say, I have several friends who will go to some lengths to avoid the Beltway.

Can’t remember if this question is covered but just as a book recommendation, Traffic: Why We Drive the Way We Do (And What It Says About Us) is a very interesting read with lots of interesting (and frequently counter-intuitive) statistics.

One of the reasons that freeways have better statistics, it that bicyclists, pedestrians and mopeds aren’t allowed on freeways. Freeways are mostly objects of similar mass travelling at similar velocities in the same direction. The exceptions can be catastrophic, but they are exceptions and not the rule. It you exclude the above categories and motorcycles, then the fatality rate is under 1 person per 10^8 miles.

Slight side track, but this is also why you should get the hell out of your car if you ever have to break down on the hard shoulder. Its another one of those cases where the perceived risk and actual risk a totally different.

Your gut feeling (particularly its nighttime and if the driver is a woman traveling alone) is that we are safer locked in our car, and that if we get out we risk getting murdered by marauding ax murders. But actually a stationary car is the most dangerous place to be next to a highway (even more so at night, as when people fall asleep at the wheel the tend to drift into the right hand “lane”, i.e. the hard shoulder). You are far more likely to get pancaked by an SUV while sitting in your car on the hard shoulder, than you are to be attacked or otherwise coming to harm outside the car (as long you as you get right off the highway, ideally behind a crash barrier, if there is one).

I don’t have any hard numbers, but I feel it’s worth pointing out that fatalities are not the only measure of safety on highways vs surface roads. It seems overwhelmingly likely that more accidents (but non-fatal ones) would occur in stop-and-go local traffic than on freeways. But even fender-bender accidents can be very painful, even if they’re not life-threatening.

I don’t even know if hard numbers exist for this, since pain (particularly to soft tissue like back and neck) is so subjective. But it stands to reason that the increased number of fender-benders on local roads would lead to an increased number of very painful, non-fatal injuries.

Not that anyone would hypothetically prefer to be killed than to have chronic back pain. But both are serious considerations in the debate.

That last sentence is why this is a terrible reason to get out of the car – it’s a good reason to get off the road. If there is no crash barrier and no way to get off the highway (which is my perception of most California freeways), stay in the car. It’s true that it’s not ideal protection, but it’s better than your skin.

But the whole point of grade-separated highways is that there isn’t so much stuff happening from all directions - the lack of cross traffic and separation from oncoming traffic make things much safer.

The roads I find scary are the fast main roads with just one lane in each direction and no central barrier. The majority of A roads in the UK are like that, with a 60mph speed limit (and traffic often going considerably faster than that), which means you often have vehicles with a relative speed of 150mph passing each other a few feet apart, head on. You don’t get that on motorways.

True… except on the Beltway (which is the highway I drive most often) there are exits / entrances every mile or so, from the left and from the right, so there truly are things happening from every direction.

One particular left entrance is a real treat (and it’s one I drive every week). You’re dumped directly into the fastest lane, generally attempting to merge into traffic where the existing vehicles take it as a personal affront that you’re trying to merge… instead of recognizing that the merger is merely attempting to enter the highway without crashing at 70 mph into a concrete barrier with unpleasant consequences for everyone.

Yeah, it’s shitty design but it’s the reality, and is one example of why people might be nervous about highway driving.

I agree with you on the nervous-making about the one-lane-each-way roads. There aren’t that many like that where I live (at the least, such a road would be too congested to allow for high speeds) but there are plenty of two-each-way roads with no separation.

Then there’s the good old-fashioned suicide lane - the centre lane can be used for overtaking in either direction :eek:

Those are pretty rare nowadays, but there’s a similar three-lane setup on the route I take to visit my parents. However the middle lane alternates between eastbound and westbound in one-mile sections, so it’s less scary: link.

On the few occasions I’ve had to pull over on hard shoulder of a California freeway it has been easy to get well off the freeway. The only time it would be a bad idea is up in the sierras where there could be a 200ft drop a couple of feet from the road.

I don’t recall ever seeing a suicide lane in the United States. I find it scary enough in places where there is a center lane that functions as a turn lane for both directions. I’ve had a couple of close calls when a car going in the opposite direction decides to turn at the same place I’m turning. Plus you have to deal with pedestrians standing in the middle lane at night that you can only see when they are silhouetted by the oncoming cars.

Another favorite is T-intersections where the right lane is always green. This gives you a double thrill or getting rear ended when you are stopped in the left lane and having someone making a wide left into your lane when you are driving in right.