2014-09-11-LBAC-min - Laserfiche WebLink

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Traffic Safety Advisory Committee Meeting: Tuesday, October 7, 2014, Parker Room Bike to Market Day: Tuesday, October 14 Quarterly Transportation ForumOctober 15, 9 am :, Selectmen’s Meeting Room Tri-Town Bike Committee meeting: Saturday, October 25, 9 am, Central School (Senior Center) Lower Level (27 Maple Street, Arlington Center) Moving Together Conference: Thursday, October 30, Boston Park Plaza Hotel Hand Outs: 1. Generic Roundabout Design from Richard Canale 2. Responses from Lincoln Lab cyclists provided by Jennifer Melot: “When we solicited comments from our bike interest mailing list, we received roughly 40 responses, which came almost entirely from people who regularly pass the \[Hartwell/Maguire\] intersection on their bicycle commute to work. The majority of cyclists thought the proposed roundabout design was a poor idea from a cycling perspective, describing similar multilane roundabouts as "terrifying" to navigate on a bicycle and citing safety concerns. Two particular concerns were being hit from behind by someone speeding around the roundabout with poor visibility, and getting "right-hooked" (where a car makes a right turn into an oncoming cyclist). People did say that a one-lane roundabout would be less frightening to them if the actual (rather than posted) speed of motorists inside the roundabout was 20 mph or lower. Several people said that they avoid larger and faster roundabouts altogether, and mentioned the possibility that having a roundabout in this important intersection would discourage people from using the otherwise excellent Minuteman Bikeway to Hartwell route to work. Research on bicyclists in roundabouts supports the concerns raised by our cycling community. According to the Dutch Design Manual for Bicycle Traffic, the safest roundabout for bicycles is a single-lane roundabout, and a roundabout with cycletracks is safer still (bike paths have a worse safety record than either alternative, perhaps because of right hooks) (1, 2). It also states that if bicycle facilities are used inside a roundabout, they must be extremely conspicuous (for example, with differently colored pavement) (1). While some studies have shown that roundabouts improve accident rates for motorists, "Roundabouts... do not have the same positive effect on the number of cyclist accidents" (3). Roundabout designs where cyclists are not separated from motorist traffic are perceived to be dangerous: "Similarly the number of cyclists that perceived the situation with a circulating cyclist and an exiting car as 'very much' or 'to a large extent' dangerous, was significantly larger in roundabouts without a cycle facility than in roundabouts with a cycle facility" (4). Furthermore, discontinuities in bicycle lanes can adversely impact the perceived safety of an entire route: "Most bicycle planners can easily recount anecdotes from citizens mentioning how ending bicycle lanes influence cyclist safety. If a system is only as good as its weakest link, then discontinuities often time comprise this weak link.