Strategy Behind the Standard

Roundabouts offer capacity advantages over other forms of junction, but they can be hazardous for cyclists. Finding a safe position to occupy in the circulatory carriageway may be difficult, and cyclists are at risk of not being noticed by drivers entering or leaving the junction at relatively high speeds.

Roundabouts account for around 20% of all reported cyclist killed or seriously injured (KSI) casualties and roundabouts designed to standard UK geometry can be hazardous for cyclists. They usually have flared entries and exits with two or more lanes and wide circulatory carriageways which are often unmarked, leading to high differences in speeds and inherent conflicts between cyclists and motor vehicles. The relatively smooth path for motor vehicles helps increase capacity but can result in high traffic speeds through the junction, particularly on large diameter roundabouts outside urban areas where traffic is free-flowing.

Finding a safe position to ride around the wide circulatory carriageway may be difficult. Cyclists are at risk of not being noticed by drivers entering or leaving the junction at relatively high speeds. Roundabouts with a dedicated left turn slip lane to increase traffic capacity pose an additional hazard for cyclists, both where the lane diverges and on the merge at the exit, where a cyclist travelling straight ahead or turning right will leave the roundabout between two fast moving traffic lanes.

Fendon Rd Dutch Style Roundabout, Cambridge

Best Practice Guidance to be used by Essex Highways

Cycle Infrastructure Design LTN 1/20 – Chapter 10.7

How the Standard Should be Assigned

There are two ways to accommodate cyclists more safely at roundabouts (depending on traffic conditions, as described in ‘What Infrastructure Should I Recommend?’):

  • Roundabouts with protected space for cycling
    • Where traffic volumes are high, and at roundabouts with high-speed geometry, provide protected space for cycling away from the carriageway, preferably with cycle priority or signal-controlled crossings of the roundabout entries and exits (or grade separation); or
  • Roundabouts for cycling in mixed traffic conditions
    • Compact or Mini-roundabouts, where traffic volumes and speeds are (or can be made) low, and the lane widths are narrow so that with other traffic cyclists can safely share the single lane entries, exits and the circulatory carriageway in the primary position.

Best Practice Example

Fendon Rd, Cambridge