Freakonomics Radio

Should Traffic Lights Be Abolished? (Ep. 454 Replay)

Thu Aug 10 2023

roundaboutstraffic safetyCarmel, Indianaefficiencypublic perceptionautonomous vehicles

Description

The episode explores the benefits of roundabouts in improving traffic safety, reducing fatalities, and increasing efficiency. It discusses the success of roundabouts in Carmel, Indiana and their impact on pedestrian safety. The cost implications of building roundabouts compared to signalized intersections are also examined. Additionally, the episode delves into public perception and challenges faced in implementing roundabouts, as well as the potential role of autonomous vehicles in navigating roundabouts. Overall, the episode highlights the potential of roundabouts as a safer and more efficient alternative to traditional intersections.

Insights

Roundabouts can save lives

Swapping out standard intersections with traffic lights for roundabouts could potentially save thousands of lives in America.

Roundabouts improve traffic safety

Roundabouts have a lower fatality rate compared to other types of intersections.

Roundabouts reduce congestion

Roundabouts improve traffic flow and reduce congestion, making them more efficient than signalized intersections for most of the day.

Roundabouts have economic benefits

Roundabouts save money by replacing stoplights and have lower maintenance costs compared to signalized intersections.

Roundabouts face public opposition

Some cities have faced public opposition or hesitation when considering roundabout projects, possibly due to the perception that roundabouts are too European.

Autonomous vehicles and roundabouts

Navigating roundabouts is a negotiation that autonomous vehicles handle by detecting objects and playing forward different scenarios. Public acceptance of driverless vehicles may be a challenge due to anxiety and perception hurdles.

Summary

Transcript

Roundabouts and Traffic Safety

00:04 - 08:01

Many crashes and traffic injuries happen at intersections controlled by traffic lights.
Roundabouts are small circular traffic intersections without traffic lights or stop signs.
Swapping out standard intersections with traffic lights for roundabouts could potentially save thousands of lives in America.
Roughly 40,000 Americans are killed each year in traffic crashes, with about a quarter of those deaths happening at intersections.
Crashes also cause millions of injuries and over a third of a trillion dollars in property damage and costs.
Roundabouts have economic benefits, lower emissions, but also technical complications like congestion at entrances.

Roundabouts in Carmel, Indiana

07:43 - 15:06

Carmel, Indiana has built more roundabouts than any other city in North America.
There are currently 133 roundabouts in Carmel, with more under construction.
Carmel accounts for nearly 2% of all roundabouts in the US.
Roundabouts have a lower fatality rate compared to other types of intersections.
In roundabouts, the death rate is 0.1% per crash, while it is 0.4% at four-way intersections and 0.9% at Y intersections.
Roundabouts force drivers to slow down, reducing the risk of accidents.
Roundabouts are safer for pedestrians and people with disabilities.
Roundabouts save money by replacing stoplights.

Safety and Efficiency of Roundabouts

15:00 - 22:28

Roundabouts are safer than intersections with conflicting traffic flows.
Carmel, Indiana has significantly fewer fatalities due to roundabouts compared to other cities in Indiana.
The UK has a high number of roundabouts and a lower rate of traffic fatalities compared to the US.
Red light cameras can make intersections safer by reducing the number of drivers rushing through yellow lights.
Converting standard intersections to roundabouts reduces fuel consumption and carbon emissions.
Roundabouts improve traffic flow and reduce congestion.
Roundabouts are more efficient than signalized intersections for most of the day.
The cost of building roundabouts is higher than signalized intersections.

Costs and Benefits of Roundabouts

22:04 - 29:31

Roundabouts can be more expensive than signalized intersections, especially when converting existing intersections due to factors like real estate and retrofitting difficulties.
Signalized intersections can cost anywhere from $250,000 to over a million dollars.
Material costs and labor costs make up about 50% each of the total cost of a signalized intersection.
Signal heads, which contain the red, yellow, and green lights, can cost around $2,000 to $3,000 each.
Poles that support the signal heads can cost around $25,000 each and take up to 10 months to get due to engineering requirements.
The control box in an intersection costs around $30,000 and is essential for operation.
Electrification of an intersection can be costly depending on wiring requirements and may range from $3 per foot to $100 per foot.
Pedestrian push buttons at crosswalks can add another $20,000 per signalized intersection.
Maintenance and repair are necessary for traffic light equipment due to various issues like hurricanes or rats damaging wiring or hardware.
Transitioning from incandescent bulbs to LED bulbs has been a major innovation in recent years but may cause visibility issues in snowy areas.
Traffic signals account for about two billion dollars in lost time annually due to delays at intersections.
Converting a four-way stop into a roundabout is generally less expensive than adding traffic lights.

Roundabouts and Public Perception

29:17 - 36:59

Building a roundabout is cheaper than adding traffic lights to an intersection in Indiana.
Operating costs of traffic lights include sending engineers to reset the timing and replacing the apparatus every 25-30 years.
Converting an intersection with traffic lights to a roundabout has a substantial cost, including buying additional land and moving underground utilities.
Roundabouts can improve commercial access by allowing more cars to move through compared to stoplights.
There is a movement in the United States to build more roundabouts, with incentives in federal transportation law and encouragement from state DOTs.
Change is hard for humans, especially elected officials who fear taking risks that may affect their re-election chances.
Some cities have faced public opposition or hesitation when considering roundabout projects.
The perception that roundabouts are too European may contribute to their unpopularity in the US.
Drivers' apprehension towards roundabouts tends to decrease once they use them and understand their benefits.

Roundabouts and Autonomous Vehicles

36:33 - 44:22

The established transportation design guidelines in the United States train drivers to rely on the transportation system for instructions.
Roundabouts require drivers to think for themselves, which can be uncomfortable and challenging.
Navigating roundabouts is a negotiation that autonomous vehicles handle by detecting objects, extracting metadata, and playing forward different scenarios.
Autonomous vehicles will eventually learn to manage various situations through exposure to stress tests.
Public acceptance of driverless vehicles may be a challenge due to anxiety and perception hurdles.
Change is often opposed initially but accepted over time when it becomes inevitable.
Roundabout acceptance has happened relatively fast in the past, with people forgetting their initial opposition after a year.
English roundabouts reflect local culture and art, while American roundabouts have more potential for creativity.