ESCALA SF-36 EN LA ENFERMEDAD DE ALZHEIMER

A number of activities are predictable and required at regular intervals, often several times per year. An example is grass cutting. The Road Manager knows that grass will grow during the rainy season and that it will need cutting perhaps midway through and shortly after the rainy season.

A condition survey therefore does not need to assess the severity of the defect in order to identify a required activity. Rather, it needs to assess the extent of the item which will require treatment at a

predictable frequency or interval. For example, the survey does not need to record the height of grass, but the area of grass which will need to be cut. Recording the area will allow the need for regular grass cutting to be identified even if it is surveyed shortly after the grass has been cut or during the dry season when it has died back. Similarly, the survey does not need to record the thickness of sediment in a drain, but the length of drain which will need to be cleared.

Many routine maintenance activities are predictable and can be scheduled. Some periodic maintenance activities are also predictable and can be scheduled, even if at a lower frequency. Scheduling activities can therefore be rapid if there is sufficient information to enable the Road Manager to estimate when the activity will be required.

With many activities, the Road Manager does not know exactly where it will be required, but is sure that it will be required somewhere along a road. For example, it is impossible to predict where erosion will occur or which culvert aperture will block, but it is likely that there will be erosion and blocked culverts

Table 3.16 Producing a safe environment for road users Accident type

Possible problem/cause Solution

Multiple vehicle

Head on

Vehicle enters oncoming lane. l Widen road.

l Remove sharp crests and inner curve obstacles to improve visibility.

l Improve and maintain road condition.

l Provide centre line markings on sealed roads, especially on bends.

l Widen road.

l Provide passing places with signs indicating spacing distance.

l Provide signs warning of narrow carriageway.

l Slow traffic with well signed traffic calming measures.

l Remove obstacles and cut vegetation to 1.5 m from carriageway.

l Provide temporary signs warning of reduced width.

l Repair damage; continue maintenance.

l Provide temporary signs warning of reduced width.

l Provide gabions or flared barriers to protect end of bridge.

l Provide rumble strips on the approach if a sealed surface.

l Provide signs warning of reduced width.

l Indicate which direction has priority over oncoming traffic.

l Provide parking/passing places.

l Improve visibility by cutting vegetation or battering back slopes.

l Sight distance must be greater than stopping distance at speed.

l Provide signs and road markings warning against overtaking.

l Seal road or use dust palliatives to eliminate or reduce dust.

l Cut vegetation at junction to increase visibility.

l Widen shoulder at junction to increase visibility.

l Provide signs warning of approaching junction on major road.

l Provide signs warning of poor road condition.

l Provide edge delineators on outside edge of shoulder.

l Provide barriers when road is embanked.

l Eliminate corrugations, ruts and potholes; continue maintenance.

l Ensure that road geometry is consistent along a road.

l Provide signs warning of speed limits.

l Encourage police to enforce speed limits. Carriageway is too narrow

for current traffic usage.

Useable width has been reduced by encroachment.

Useable width has been reduced by road damage. Bridge deck is narrower than carriageway.

Dangerous overtaking manoeuvres.

Side impact

Restart. Vehicle stops at junction, restarts and is then hit from the side.

Single vehicle

Run off road

Vehicle loses control due to poor condition.

Vehicle loses control due to high speed.

Overshoot. Vehicle does not stop at junction and is then hit from the side.

Continued ....

l Provide signs warning of approaching junction on minor road.

l Provide large sign on major road opposite the minor road entry.

l Cut vegetation at junction to show vehicles approaching from side.

l Avoid tight bends where possible.

l Provide barriers and edge delineators on outside of the bend.

l Provide signs and road markings warning of tight bend.

l Widen and/or super-elevate the carriageway around the bend.

l Improve the skid resistance of the road surface.

l Provide edge delineators on outside edge of shoulder.

l Flatten side slope to 1:5 or less.

l Increase shoulder width between carriageway and side drain.

l Excavate more mitre drains and reduce side drain depth.

l Cover drains with concrete slabs in urban areas.

l Excavate a side drain shape which will not trap vehicle wheels.

l Remove debris as soon as possible.

l Provide warning signs if immediate removal is not possible.

l Provide impact protection to head wall.

l Lengthen culvert barrel and re-site headwalls.

l Paint the headwall white for greater visibility.

l Remove tree and other vegetation within 1.5 m of carriageway.

l Paint the tree trunk white for greater visibility.

l Re-site all obstacles greater than 1.5 m from carriageway. Table 3.16 (Continued) Producing a safe environment for road users

Accident type

Possible problem/cause Solution

Run off road

Vehicle runs off road at a tight bend.

Vehicle veers off road and cannot recover.

Hit object on carriageway Vehicle hits debris left on road.

Hit object alongside carriageway Vehicle hits culvert head wall.

Vehicle hits tree or other obstacle.

Vulnerable road users

Pedestrians, cyclists, animal carts, etc. Traffic speeds are too high

in towns and villages.

Road is too narrow for the mix of road users.

l Provide signs warning of local speed limits.

l Encourage police to enforce local speed limits.

l Calm traffic with speed humps, road narrowings, raised level pedestrian crossings & low speed zones.

l Segregate road users using edge delineators, road markings, kerbs or barriers, especially on bridges.

l Retain construction detours for use by vulnerable road users.

l Provide an off-carriageway footpath/cycle lane.

l Widen drain to act as a dry season footpath.

l Widen shoulder to 1.5 metres; pave the shoulder.

l Ensure vegetation is regularly cut.

l Flatten drain slopes to provide an emergency refuge for cyclists.

l Provide off-carriageway areas for market traders.

l Provide formal bus stop lay-bys.

l Provide an off-carriageway bus park. Poorly located or non-existent

bus stops.

Some of these solutions are described on Activity Planning Sheets in Annex G. For other solutions, more specialist design, construction and maintenance guidance should be sought.

and it is therefore worth scheduling that activity. Over time the Road Manager will get used to the quantity which is likely to be required every time the activity is scheduled.