Day: 2011-04-07

Putting on the Brakes: Mankind Nears the End of the Age of Speed

| David Levinson

WSJ:

Putting on the Brakes: Mankind Nears the End of the Age of Speed : “”

 

 

The human race is slowing down.

 

When the U.S. space shuttle completes its final flight, planned for June, mankind will take another step back from its top speed. Space shuttles are the fastest reusable manned vehicles ever built. Their maximum was only exceeded by single-shot moon rockets.

The shuttles’ retirement follows the grounding over recent years of other ultrafast people carriers, including the supersonic Concorde and the speedier SR-71 Blackbird spy plane. With nothing ready to replace them, our species is decelerating—perhaps for the first time in history.

It has been a good two-century sprint, says Neil Armstrong, who in 1969 covered almost 240,000 miles in less than four days to plant the first human footprint on the Moon. Through the 18th century, he noted in an email exchange, humans could travel by foot or horse at approximately six miles per hour. “In the 19th, with trains, they reached 60 mph. In the 20th, with jet aircraft, we could travel at 600 mph. Can we expect 6,000 mph in the 21st?” he wondered.

“It does not seem likely,” Mr. Armstrong continued, although he holds out some hope.

The trappings of humanity’s race are on display in London’s Science Museum. At one end of a cavernous hall sits the first practical steam locomotive, designed in 1829 by George Stephenson, an English engineer. It was called “the Rocket” for its previously unimaginable speed of 29 mph.

Before Mr. Stephenson’s marvel of wood and cast iron, “express” generally involved a pony. Railroads, Britain’s gift to the world, shrank continents and slashed travel time.

 

(Via Alan Pisarski.)

The top speed may be dropping, but I think average speeds will continue to rise.

Like John Lithgow in Footloose, Denver kills the Barnes Dance

| David Levinson

The Denver Post reports some sad news …. Denver to eliminate diagonal crossings at intersections

A tradition that started 60 years ago in downtown Denver and became commonplace in intersections around the world is about to end in its city of origin as city traffic engineers give last call to the ‘Barnes Dance.’

The maneuver that stops traffic in all directions and gives pedestrians unfettered access — allowing people to briefly dance in the streets as they meet in the middle and dodge and weave to get by — will end May 14 as the city reconfigures its traffic signals.

The move is necessary because of transportation changes that will affect downtown beginning next month, including longer Regional Transportation District light-rail trains and longer crosswalk intervals.

So in brief, Light Rail impedes pedestrian mobility. (Somehow I think there were other solutions).

For those not familiar, see the wikipedia article on Barnes Dance, and the famous traffic engineer Henry Barnes.

Rail Transit Benefit Cost Analysis – Nonuser benefits

| David Levinson

There is a nice debate between Peter Gordon and Paige Kolesar, Robert Cervero and Erick Guerra, commented upon by Lisa Schweitzer on non-user benefits from rail transit investments. This appears in
Public Works Management and Policy — April 2011, 16 (2)

Unfortunately, this is behind a paywall, so if you don’t have a university, it may be difficult or pricey to get. (boo!).
Gordon and Kolesar:

Rail transit systems in modern American cities typically underperform. In light of high costs and low ridership, the cost-benefit results have been poor. But advocates often suggest that external (non-rider) benefits could soften these conclusions. In this paper we include recently published estimates of such non-rider benefits in the cost-benefit analysis. Adding these to recently published data for costs and ridership, we examine 34 post-World War II U.S. rail transit systems (8 commuter rail, 6 heavy rail and 20 light rail). The inclusion of the non-rider benefits does not change the negative assessment. In fact, sensitivity analyses that double the estimated non-rider benefits and/or double transit ridership also leave us with poor performance readings. Advocates who suggest that there are still other benefits that we have not included (always a possibility) have a high hurdle to clear.

Cervero and Guerra:

The debate over the costs and benefits of rail passenger transit is lively, deep, and often ideological. As with most polemical debates, the truth probably lies somewhere in the middle of extreme views. Some rail systems have benefits that outweigh their costs, while others do not. Applying a commonly used transit-fare price elasticity to 24 of the largest light and heavy rail systems in the United States and Puerto Rico, assuming a linear demand curve, and accounting for a counterfactual scenario, we find that just over half of the systems have net social benefits. Although Los Angeles’ rail system does not “pass” our back-of-the-envelope cost–benefit analysis, as the network expands, it will begin to mimic the regional spatial coverage and connectivity of its chief competitor—the auto-freeway system—and approach the fare recovery rates of other large, dense American cities.

(Via Peter Gordon’s blog.)

Texas House backs plan to allow 85 mph speed limit

| David Levinson

AP Reports: Texas House backs plan to allow 85 mph speed limit:

“AUSTIN, Texas — The Texas House approved a bill that would allow the speed limit on some highways to be raised to 85 mph, which would be the highest in the nation.

The measure passed Wednesday on a voice vote was part of a larger transportation bill. It would authorize the Texas Department of Transportation to raise the speed limit on designated lanes or entire stretches of roadway after doing engineering and traffic studies, the Dallas Morning News reported Thursday.

The Senate is considering a similar bill.

‘They have high-speed roadways in Europe, and there could be some merit in having some of those highways in Texas,’ said Rep. Lois Kolkhorst of Brenham, who introduced the bill. ‘Given the right engineering, we should consider it.’

Texas currently has more than 520 miles of interstate highways where the speed limit is 80 mph.

One such stretch of Interstate 10 ‘is as nice a road as you can build; it’s flat with a long line of sight, wide lanes and good shoulders,’ said Rep. Joe Pickett of El Paso. ‘For people like us who travel that long distance, it could be good’ to raise the limit to 85 mph, he said.

Some auto insurers oppose the measure, citing safety concerns.

‘Obviously, the two things that kill most people on our highways are speed and alcohol. Increasing it to 85, or even 75, will have a dramatic impact on the death and injury rate on those highways where it’s implemented,’ said Jerry Johns, a spokesman for the Southwestern Insurance Information Service.

He said drivers already exceed 70 mph highway speed limits.

‘But 85 mph is simply too fast to drive even on a flat road. Any little hitch can cause an accident at that speed. There is still traffic on those roads, and to drive 85 mph is simply ludicrous,’ he said.

The Transportation Department hasn’t done the speed and safety analyses of roadways the legislation would require, said department spokeswoman Kelli Petras.

‘It would be awesome to travel it, but you’d have to look at the safety and other factors,’ she said.”

The safety question is interesting, since, according to Lave and Elias raising the speed limit on Interstates in the 1980s and 1990s had overall (statewide) beneficial effects, by attracting drivers from less safe non-interstates to the Interstates, where higher speeds are more likely to be forgiven by the road. They write: “We find that the 65 mph limit reduced statewide fatality rates by 3.4% to 5.1%,holding constant the effects of long-term trend, driving exposure,seat belt laws,and economic factors.” Of course, other research has found the fatality rates on interstates themselves were generally higher.
This is then definitely good from a mobility perspective, possibly good from a safety perspective (though there may be limits to the implications of the Lave and Elias study, just because moving from 55 to 65 reduced deaths doesn’t necessarily mean moving from 75 to 85 will also reduce overall deaths), and probably bad from an energy and environment perspective, since energy consumption will most certainly rise with faster speeds.

A bridge for Stillwater

| David Levinson

250px-Stillwater_Minnesota

The Stillwater Bridge question is back in the news, with Governor Dayton and Representative Bachmann endorsing a new four lane bridge to connect to the future development in Wisconsin. Senator Franken is apparently undecided. Franken takes a bridge tour. MnDOT’s information page is here The costs are quite high MnDOT estimates $633 M for a four-lane bridge.

We looked at the travel demands of the proposed Stillwater Bridge for MnDOT last year. The results are here. To summarize, we wrote:

StillwaterNew

“This report is prepared … to assess the expected traveler impacts of replacing or not replacing the Saint Croix River Bridge in Stillwater, Minnesota. The model that has previously been used to evaluate different Lafayette Bridge replacement scenarios is applied, using the 20 county (“collar counties”) network from the Metropolitan Council and best estimates of 2010 land uses (population and employment). The model evaluates changes in travel cost due to network reconfigurations corresponding to different scenarios. These costs would need to be compared against construction and ongoing operations and maintenance costs, and do not account for factors such as travel time reliability, the value of a redundant network for planned or unplanned closures, or changes in land use.

It can be safely assumed that were a wider, faster bridge constructed there would be more development, and thus more travel demand from the Wisconsin side of the Saint Croix River. If no replacement bridge were built, we can assume that less growth (if any) would occur, and cross-river traffic would diminish. This model does not account for changes in land use, as we do not believe this has been accurately forecast for scenarios both with and without the bridge, but does account for changes in demand given the current land use under different network configurations. This is denoted as “Variable Trip Tables” in the report.

Compared to the baseline (a replacement 2 lane bridge in the same location) according to the model, Construction Alternative 1, a new 4 lane bridge, produces an economic gain of $1.8 million per year.

Compared to that same baseline, Construction Alternative 3, no replacement bridge at all, results in an economic loss on the order of $34.1 million per year according to the model.”

Again, this comes down both to Benefit / Cost analysis (does this pass a test?) and priorities (does this count as “Fix It First”?). I think building a four lane bridge to replace a two lane bridge does not fully count as “preservation”, but rather as “expansion”. Given the state of the network, and the need to give priority to preservation, a four lane bridge violates that principal. As to whether a four lane bridge passes a B/C test, or better yet, a market test of whether a private firm would build it, the answer is clearly no. This four-lane bridge would not have enough demand to pay the tolls required to fund it. That should tell you something about its true necessity. The Franken article cited above suggested Wisconsin wasn’t interested in funding it. Since the majority of benefits for the bridge accrue to Wisconsin land owners, it makes no sense for Minnesota to lead on this.