To the editor:

As I read the articles about the traffic circles in Riverside and West Barrington, I think that we need to be clearer when we talk about modern roundabouts.  

The locations in question in Riverside and West Barrington could benefit of some geometric modifications to be closer to what the industry identifies as modern roundabouts. The safety statistics noted by RIDOT are accurate for modern roundabouts, as they have been proven by the Insurance Institute of Highway Safety. This is the organization of insurance companies that has a vested interest to improve safety, as their expenses paying for claims is reduced.  

A modern roundabout is a Federal Highway Administration (FHWA) Proven Safety Countermeasure featuring a circular intersection with counterclockwise flow, yield-on-entry control, and channelized approaches designed to slow speeds and reduce severe crashes.

Key design principles

• Yield Control: Entering traffic must yield to vehicles already circulating in the roadway.

• Deflection: Geometric curvature forces horizontal deflection, managing speeds to typically 15–25 mph.

• Splitter Islands: Raised islands on approaches calm traffic, prevent wrong-way movements, and provide pedestrian refuge.

• Truck Aprons: Mountable inner portions of the central island accommodate large commercial vehicles or emergency apparatus.

Common categories

• Mini-Roundabouts: Small-footprint solutions for low-speed urban streets.

• Single-Lane: Single-lane entry and circulation suited for moderate volumes.

• Multilane: Multi-entry configurations for higher capacity on major corridors.

While the circular intersections in the area can be qualified as single lane roundabouts, they lack the most important characteristic of a modern design: Deflection at entry. 

A newly designed roundabout would allow drivers to see curbing and the center island. Also, the geometry of the approach should be conducive to reduce the speeds. For the circle in Riverside, three of the four approaches to the circle lack any deflection at all. The geometry is not guiding a driver to intuitively slow down. The Willett Avenue approach has some deflection, but the radius of the curve as you approach the circle may not be enough to slow the speeds of motor vehicles.

For the circle in West Barrington, the deflection is so subtle that it does not slow you down enough to give the right of way to the traffic already in the circle, and the merge from Washington Road onto County Road has no deflection at all.

Calling these intersections modern roundabouts is a bit of a stretch. 

These intersections need some additional curb work to truly retrofit these circles into a modern design.

Francisco Lovera

Barrington