European freeways

[US 41]

Are European freeways cheaper to build than our interestates? By putting guardrails in the center of the highway, not as much land is needed and the grass doesn't need mowed.. Bridges crossing the highway don't need to be as long. The lanes seem to be a little narrower too. I wonder if European style freeways will become common in the US one day or if we will continue to build highways with really wide medians.

[rschen7754]

Well, in US urban areas, there's often a guardrail and narrow median, though the bridges and extra lanes might drive up the cost.

[SteveG1988]

Their cars are built narrower.

If you want a good example, compare a chevrolet venture with any other US minivan

[vdeane]

The four lanes, narrow median, and guiderail reminds me a lot of I-490.
http://goo.gl/maps/w3lms

[english si]

I believe the standard rural autoroute/autobahn/autopista/autrostrada/etc lane width is 3.5m. The UK and Ireland use 3.6m (or is it 3.65?) as it used to be 12'

[Road Hog]

Real estate in Europe is at a premium unlike in most of the rural U.S., so sprawling ROWs are prohibitively expensive.

[Chris]

Most of the freeway lanes in Europe are 3.5 - 3.75 m wide. That's 11.5 - 12.3 foot.

Land prices in Europe are higher, because much more land is cultivated when compared to the dense forests of the southeast or the high plains. It's more expensive to get a wide right-of-way at productive farmland than it is in the middle of nowhere in Wyoming.

Wide freeways do exist though. I have some examples from the Netherlands:


024 by Chriszwolle, on Flickr


A6-7 by Chriszwolle, on Flickr


IMG_1870 by Chriszwolle, on Flickr


A28 Dwingeloo by Chriszwolle, on Flickr

[firefly]

Are European freeways cheaper to build than our interestates?

Don't be too concerned about the opulent width of the central reservation of rural freeways in the USA. This is just a clear sign that land is extremely cheap. And assumed that environmental requirements are nowhere near as rigorous as in Europe it should be way cheaper to build roads of any sort in rural areas in the USA.

Their cars are built narrower.

If you want a good example, compare a chevrolet venture with any other US minivan

The width of a lane is contingent on the width of an HGV rather than a car though. And I doubt that American HGVs are much wider than European ones. Hence the similar lane width on both sides of the Atlantic.

[J N Winkler]

I believe the standard rural autoroute/autobahn/autopista/autrostrada/etc lane width is 3.5m. The UK and Ireland use 3.6m (or is it 3.65?) as it used to be 12'

The UK has had 12 ft instead of 11 ft as the unit lane width for motorways largely because John Boyd-Carpenter, who at the time (1955) was Minister of Transport, dictated that motorway design standards should make as few compromises as practical on the basis of cost.  Consensus among the engineers and civil servants at the Ministry was actually in favor of 11 ft as the unit lane width, partially on the basis of lorry overtaking studies which the Road Research Laboratory had carried out in the late 1940's and early 1950's.  Ezra Hauer (an Israeli/Canadian road safety researcher working out of the University of Toronto) used to have, and may still have, online some reviews of safety studies which generally find that the optimum unit lane width for safety is between 11 ft and 12 ft but actually slightly closer to 11 ft.

Engineering standards for high-type roads on both sides of the Atlantic (including freeways and motorways) stabilized as early as 1940 with unit lane widths generally between 11 ft and 12 ft, though Britain hung on to a 10 ft option for roads that did not carry heavy truck volumes.

Land prices in Europe are higher, because much more land is cultivated when compared to the dense forests of the southeast or the high plains. It's more expensive to get a wide right-of-way at productive farmland than it is in the middle of nowhere in Wyoming.

In Britain, wide medians were studied as a design option in the early 1960's.  They have a number of technical advantages:  no headlamp dazzle, no need to provide heavy central barriers, greatly reduced risk of vehicles crossing the median.  However, it was found that the cost of land necessary to provide a central reservation of reasonable width (I can't remember the exact width--maybe 30 ft?) was approximately the same as constructing an additional lane in each direction plus a central barrier.  There are some lengths of motorway in Britain (M6 through Cumbria, M62 over the Pennines, etc.) that have wide central reservations as a result of separated carriageways, but these are uniformly in marginal land that has low potential for cultivation.



On the issue of cost generally, it is hard to do comparisons between the US and western Europe, not just because of land.  Some other factors that come to mind:

*  Construction materials (asphalt, concrete, etc.) are generally more expensive in Europe, even with purchasing power parity taken into consideration, in part because of higher energy costs.

*  In Europe, a large share of land-related costs are in fact planning costs.  In the US the total land cost (including planning cost) for a typical big-box development is about $2 million; in the UK it is around £20 million.

*  Expectations for durability are different.  In the US design lives of 25 years for roads and 75 years for bridges are common; in the UK, for example, these values are 40 years and 120 years respectively.

*  Engineering standards are different.  For example, most European countries like to separate the traffic and structural functions of bridge decks.  This means bridge decks generally have a structural component topped by a waterproofing membrane and then a running surface.  The surfacing can be replaced easily, the waterproofing is replaced about as often as we replace whole bridge decks, and the structural component is left essentially untouched for decades.  European bridge engineers don't understand why we like to burn money replacing bridge decks so often.

[SteveG1988]

At one time the PA turnpike resembled a western european freeway

[Revive 755]

Are European freeways cheaper to build than our interestates? By putting guardrails in the center of the highway, not as much land is needed and the grass doesn't need mowed.. Bridges crossing the highway don't need to be as long.

If they wanted to save, why even have the guardrail and grass instead of just a small shoulder with a jersey barrier?

As for freeways in the US that resemble European routes, all parts of I-44 in Missouri need are steel guardrails instead of cable barriers and it might qualify.

Section just west of Rolla

A small section between Springfield and Lebanon


As for the US ever making the narrow median more common that the wide grass median for rural freeways, other than isolated cases such as MO 21 near Hillsboro (Streetview; was built like this to save money), I doubt it.  IIRC, there are higher crash rates with a narrower median, while a grass median with the cable barrier down the center gives a little more time to recover.  The narrower median also reduces options for future expansion

[firefly]

If they wanted to save, why even have the guardrail and grass instead of just a small shoulder with a jersey barrier?

Concrete barriers are used for 2 decades already. They might be cheaper for the road operator. Yet, they aren't particular pretty and they are less favourable for vehicles which crash into the barrier.

[Brandon]

If they wanted to save, why even have the guardrail and grass instead of just a small shoulder with a jersey barrier?

Concrete barriers are used for 2 decades already. They might be cheaper for the road operator. Yet, they aren't particular pretty and they are less favourable for vehicles which crash into the barrier.

However, they are better at deflecting vehicles and keeping errant vehicles on their side of the barrier.  I'd rather have them then metal.

[jakeroot]

I think this is an appropriate thread to express my opinion that the UK's lane width seems just about perfect. Not too small that you spend your entire time on the horn to keep from having an oncoming collision, but not so wide that driver confidence is high and therefore resulting in a higher crash rate.

I remember driving from Glasgow to Inverness along the A82, and that was the thinnest two-lane road I have ever driven on. And the best part was, it was such a white-knuckle experience, I never once felt like picking up my phone. It was honestly lovely, me and the 5 Series.

On the UK Motorways, I especially like the newer fashion of red asphalt in the center of the dual carriageway. Not sure of its function but it looks nice.

[Truvelo]

Am I right in saying there is now a policy of gradually introducing barriers on wide US freeway medians? I've seen many rural sections with 100' medians and a shiny new rope style barrier running down the middle.

[J N Winkler]

Am I right in saying there is now a policy of gradually introducing barriers on wide US freeway medians? I've seen many rural sections with 100' medians and a shiny new rope style barrier running down the middle.

In some states there may be, but that type of provision is uneconomic and I don't think it will ever be rolled out as a nationwide standard.  The rate of cross-median accidents falls so drastically when median width increases from 40 ft to 60 ft that it becomes difficult to make an economic case for use of median barriers at 60 ft and higher.