Measuring the LSD effect: 36 percent improvement

The curve at Lake Shore Drive and Oak Street in Chicago is a favorite nudge. The tight turn makes it one of the city’s most dangerous curves. To try and limit wrecks, in September 2006 the city painted a series of white lines perpendicular to traveling cars. The lines get progressively narrower as drivers approach the sharpest point of the curve, giving them the illusion of speeding up, and nudging them to tap their brakes.

Exactly how effective have these lines been in preventing crashes? Until now, only anecdotal accounts have been available. What about a little hard data? According to an analysis conducted by city traffic engineers, there were 36 percent fewer crashes in the six months after the lines were painted compared to the same 6-month period the year before (September 2006 – March 2007 and September 2005 – March 2006).

To see if it could make the road even safer, the city installed a series of overhead flashing beacons, yellow and black chevron alignment signs, and warning signs posting the reduced advisory speed limit. Again, accidents fell – 47 percent over a 6-month period (March 2007 – August 2007 and March 2006 – August 2006). Keep in mind that the post-six-month period effect included both the signs and the lines.

How much more these calming signals will affect driving is unknown, but the city considers the numbers a sign of success. A drive between the North and South Sides is now safer and quicker for everyone.

Hat tip: Chicago Department of Transportation for providing its data.

Confusing choice architecture: Don’t text, but check out our tweets

Talk about mixed messages.

At least 22 states that ban texting while driving offer some type of service that allows motorists to get information about traffic tie-ups, road conditions or emergencies via Twitter.

Sadly, the Nudge blog’s home state of Illinois is one of them. Full story here.

What if a speed limit sign told you the most efficient speed to drive?

Econs don’t always drive the speed limit. They know that sometimes driving the limit (or over it) can get you stuck behind slower cars or always stopping and restarting at red lights. Gridlock guru Tom Vanderbilt recently came across something called the TrafficFlow Manager that tries to help Humans drive more like Econs.

(It is) a driver alert display that works with traffic signal timing to alleviate traffic congestion. When mounted along a route with timed traffic signals, the display informs drivers that the lights are synchronized and lets them know the proper speed they must maintain in order to avoid having to stop for a red light.

Traffic engineers already try to set lights to improve traffic flow patterns. This “smart” device links the lights to the signs. The sign’s manufacturer says this kind of synchronization reduces delays and saves fuel.

Crooked lines, careful drivers?

Governing magazine reports on a traffic experiment by the Virginia Department of Transportation that uses zigzag markings on roadways to try and make motorists slow down for pedestrians.

VDOT got the idea to experiment with the zigzags from the U.K., where they are used as no-parking areas in order to give pedestrians a clear line of sight prior to crossing, and in Australia where they are used to warn drivers to slow down due to crossings they may not be able to see.

Loss aversion on the road

Erel Avineri of the Centre for Transport & Society looks at traffic from the perspective of a Human, not an Econ. Standard economic models of people seem to do a poor job anticipating what people do on the road. Using models from behavioral economics and psychology, Avineri is interested what influences our boundedly rational travel behavior. What kind of feedback might change it? What effect do our interactions with others on the road have? According to his web site, he is “exploring how to change travellers’ behaviour in a way that does not limit their freedom of choice (for example by ‘nudging’).” In some interesting research, he applied the lessons of loss aversion to everyday decision making by travelers. We asked Avineri to share his insights with Nudge blog readers.

Continue reading the post here.

More on fake potholes

Traffic guru Tom Vanderbilt, author of Traffic (appropriately), fills in the blanks on the fake potholes. They are part of a marketing campaign for car suspension systems (which a Nudge blog reader noticed too).

In reality, they were used as part of an advertisement for Pioneer Suspension, a vehicle suspension supplier. The ad was intended to suggest to drivers that, with Pioneer Suspension fitted to their vehicles, they would enjoy a smooth ride even on rough roads. Information about the ad published on the Ads of The World website…According to Ads of the World, the ad was created by Advertising Agency, Y&R Everest, Mumbai, India in 2007. It is unclear under what conditions or circumstances the advertising tactic was carried out. As many commentators have noted, unless the tactic was used in very controlled conditions, such fake potholes could actually be quite dangerous. Approaching drivers could swerve suddenly to avoid the “pothole” and serious accidents could result.

More at How We Drive.

Watch out for potholes

More nudges from the world of traffic. Try these when speed bumps, real or fake, don’t work.

From what we can tell so far, they are fake.

Hat tip: Christopher Hsee

Singing in the lane

The always interesting Traffic author Tom Vanderbilt points out a possible nudge solution for “left-lane” bandits, who are drivers that stay in what is supposed to be a lane for passing slower cars.

One issue, of course, is that for some people, the fastest drivers, the left-lane becomes their de facto lane, and they may force out dozens of drivers (necessitating all kinds of disruptive lane changes) for their own benefit. This raises another possibility. The road could be grooved in such a way, as in Japan’s Melody Road (that’s an engineer inspecting the road pictured above) to produce a certain sound at a certain speed. Grooving could presumably be laid so that drivers going over a certain speed produced a really grating, revulsive sound (music might be tricky as one person’s annoyance would be another’s delight). In a sort of Nudge-like way, drivers could choose to stay in the unpleasant lane if they wished, but they would be subtly steered toward the more harmonic travel lanes.

A video of Melody Road is below. (Unless you speak Japanese, you’re only going to hear the sweet sound of asphalt)

A traffic light you will not miss

It’s a nudge straight out of the future, or at least a science fiction fantasy: Designer Hanyoung Lee’s “Virtual Wall,” a ten-foot high curtain of plasma laser beams. At the moment, there are no plans to produce these on a mass scale. In fact, it hasn’t even gotten off the drawing board.

Hat tip: Sendhil Mullainathan