New Princeton Alexander Street Roundabout Is Open!

New roundabout at Alexander Street in Princeton. (Click to expand.)

New roundabout in Princeton, looking south along Alexander Street. The WaWa and University Place are accessed via an exit at the left of the picture. (Click to expand.)

A roundabout! Does that word fill you with fear? Well, it’s time to get over it, because Princeton has a new roundabout, at the intersection of Alexander Street and University Place, near the old Dinky Station. This road is one of the busiest entry points to Princeton, so the success of the new traffic layout is essential. We went by to see how the new roundabout looks.

Roundabouts are not always popular with car drivers, and last week, an article at urban planning blog ‘Better! Cities and Towns’ argued that modern roundabouts are often no good for pedestrians. The roundabout at Alexander Street is being constructed as part of Princeton University’s ‘Arts and Transit’ project, and a major objective is to link the buildings of Princeton University on either side of Alexander Street. A large number of students walk and cycle across this thoroughfare to reach residential areas such as Forbes College on the west side. Fortunately, this new roundabout includes signficant signage and striping to indicate pedestrian walkways, but we will have to see how well it performs in practice.

Pedestrian crossing with international-style striped crosswalk, signage and sharrows. (Click to expand.)

Pedestrian crossing with international-style striped crosswalk, signage and sharrows. (Click to expand.)

Cyclists may also find roundabouts challenging. In this case, there are ‘shared lane arrows’ or ‘sharrows’ to try to designate that cyclists are expected to occupy the full travel lane when entering and exiting the roundabout. Roundabouts are potentially dangerous if a cyclist stays to the right instead of occupying the full lane, because a car exiting the roundabout might strike the cyclist in a ‘right hook‘.  Not all cyclists are aware that riding in the middle of a travel lane is frequently the safest place to be, and that New Jersey law allows cycling in a middle of a lane when required for safety.

'Shared Lane' marking (sharrow) up close indicates correct lane position for bikes - i.e. right in the middle of the lane. (click to expand.)

‘Shared Lane’ marking (sharrow) up close indicates correct lane position for bikes – i.e. right in the middle of the lane. (click to expand.)

It will be interesting to see how the roundabout performs. It was doing fine under Superbowl-levels of traffic, but its first day of action is predicted to feature heavy snow in the morning rush hour. Most (but not all) car drivers using the roundabout last night seemed to ‘get’ how it works. You have to give way to traffic already on the roundabout. That does not mean that you have to stop before you enter the roundabout. If you do that, there is a very good chance  of a rear-end crash, as a trailing driver will expect you to drive straight onto the roundabout if there are no vehicles already on it.

Watch these two cars- these drivers are doing it right:

What do you think of the new roundabout? Do you think it will improve traffic flow on Alexander Street? Let us know in the comments!

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4 Responses to New Princeton Alexander Street Roundabout Is Open!

  1. I like biking through a roundabout but I’m a farily skilled and confident cyclist. I’m actually impressed that the design called for sharrows to be used in the roundabout approaches as many other roundabout solutions for cyclists are much more “pedestrian” and often poorly executed at that. Still the streets, at least Alexander, leading into the roundabout will need to have something more that sharrows to properly accomodate cyclists, namely bike lanes. Even experienced cyclists like me greatly prefer a lane of our own.

    Don’t forget Princeton, “Sharrows are not a bike plan!”

    Sharrows Are Not A Bike Plan


    You will need to do more than sharrows to get more than us highly experienced cyclists to ride around town.

  2. ScottRAB says:

    The best modern roundabout design for cyclists provides two choices. The more confident cyclist should merge with through traffic and circulate like a motorist. This is made easier by the low-speed operational environment of the modern roundabout.
    http://vimeo.com/54317041 and http://vimeo.com/61988764
    The less confident cyclist should be provided a ramp to exit the street and use a shared use path around the roundabout. Such paths are at least ten feet wide and cyclist should operate a low speeds, crossing at the pedestrian crossings. http://tinyurl.com/roundabouts-and-bikes
    Sometimes space constraints, as with other intersection types, limit ideal design.

    • Agreed! But the devil is in the in the details. A new roundabout and bike lanes built in Trenton last year tried the design you mention but fails due to the final contruction details. The “pedestrian” route for cyclist is flat out dangerous to navigate at speed above 4mph.

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