Road marking, signposting and public lighting .1 Road marking

Typical pavement markings for roundabouts consist of delineating the entries and the circulating carriageway. Approach and entry pavement markings consist of give way lines, symbol markings and channelizingmarkings (see also figure 37).

Give way marking

Basically, the traffic in a roundabout has right of way. Therefore, give way white triangles (sharks’ teeth) should be used to demarcate the entry approach from the circulating roadway. The symbols should be located along the inscribed circle at all roundabouts. No sharks’ teeth should be placed to demarcate the exit from the circulating roadway, but a dotted line should also be located along the inscribed circle to guide motorists who are not exiting.

Road markings

Outside the built up area, a ‘symbolic’ give way road marking can be used upstream of the give way line, as shown in Figure 34. This road marking reinforces the give way situation. Pavement markings are provided around raised splitter islands to enhance driver recognition of the changing roadway. For small splitter islands, the island may consist of pavement markings only.

Pedestrians

Because the pedestrian crossing at a roundabout should be located away (> 5 m) from the give way line, it is important to channelizing pedestrians to the appropriate crossing location, even when pedestrians have

no right of way (informal crossing). These markings should not be construed as a safety device. The markings provide guidance for pedestrians in navigating a roundabout and provide a visual cue to drivers where pedestrians may be within the road area. The channelizing markings are 0.10 m wide and have a length of 0.3 to 0.6 m. The gap between the lines is the same as the line length. The crossing markings should be installed across both the entry and exit of each leg and across any right turn bypass. The markings should be aligned with the ramps and the pedestrian refuge in the splitter island and have markings that are generally perpendicular to the flow of vehicular traffic.

It is also possible to give pedestrians priority by using a zebra crossing. The zebra crossing provides a higher degree of visibility than a traditional transverse crossing marking in roundabout applications.

However, outside built-up areas such provisions are not preferred, as indicated in section 4.6.1. Zebra crossings should not be used where the 85^th percentile speed at the crosswalk exceeds 50 km/h.

Give way road marking (Poland) Give way signs (France) Figure 34: Give way road marking and signs

Cyclists

If cyclists use a separate cycle path and the cyclists have no right of way, the crossing should be indicated by cannelized markings. These markings are 0.10 to 0.20 m wide and have a length of 0.3 to 0.6 m. The cycle path should have give way road markings.

4.7.2 Signposting and signing

Signposting

At roundabouts with or without splitter islands, a central signpost is located in the centre island. To make the signs better visible at night, the signs have to be made of retro reflective material. To prevent insecure driving, road users need to know what exit to take on a roundabout. To accomplish this, signposts have to be placed well in advance of the roundabout (see figure 35). Signposts are also necessary on the exits.

Signing

To increase the visibility of the centre island outside built-up areas, a sign with the driving direction combined with a warning fence can be placed directly across the approaching leg (see figures 36 and 37).

A give way sign is placed just before the give way road markings, often placed on both sides of the entry lane. In situations where the roundabout can be unexpected for approaching road users it is preferred to place a warning sign ‘roundabout’ 150 to 200 m before the roundabout.

Signposting (the Netherlands) Signposting (France) Figure 35: Signposting in advance of the roundabout

Signing on splitter island and central island (France)

Signing on central island (the Netherlands)

Figure 36: Give way signs on both sides of entry

4.7.3 Public lighting

Lighting is commonly used at roundabouts because the central island presents an obstacle to traffic that must be seen at the required visibility distance. At night with only (dimmed) headlights, this will not be possible. For a roundabout to operate satisfactorily, a driver must be able to enter the roundabout, move through the circulating traffic and diverge from the circulating flow in a safe and efficient manner. To accomplish this, a driver must be able to perceive the general layout and operation of the intersection in time to make the appropriate manoeuvres. Adequate lighting should therefore be provided at all roundabouts. At night the roundabout has to be as visible as at daytime.

The positioning of the public lighting must make the roundabout recognizable. If the roads leading to the roundabout are not lighted, it is better to place lighting on the roads as an introduction to the roundabout.

At the roundabout itself it is preferable to place the lighting outside the roundabout. In this way misreading of the design is prevented and the roundabout is better noticed.

Figure 37: Signing for roundabouts in the Netherlands [3]

Additional recommendations with regard to lighting are:

– Outside built-up areas the connecting roads have to be lighted over at least 80 to 100 m (approximately 3 light posts). This helps drivers to adapt their vision from the illuminated environment of the roundabout back into the dark environment of the exiting roadway, which takes approximately 1 to 2 seconds. In addition, no short distance dark areas should be allowed between two consecutive illuminated areas.

– To accentuate the (circular) shape of the roundabout normally eight light posts are needed.

– Good illumination should be provided on the approach to the splitter islands, at all conflict areas where traffic is entering the circulating flow, and at all places where the traffic exits.

– Special consideration should be given to lighting pedestrian and cyclists crossings.

– Ground level lighting within the centre island that shines upwards towards objects in the centre island can improve the visibility of the roundabout.

– With regard to the placement of the public lighting poles, the movement of large trucks and buses need to be considered.

– The centre island has to be clearly recognizable. Lighted signposting therefore is preferred.