Highway and Pavement engineering, Highway pavement surface elements.

1. Medians and Median Barriers
Functions-
• Separates the opposite stream of traffic.
• Reserves the space for future development.
• Reduces headlight glare by accommodating vegetation.
• Improves aesthetic appearance
 General Requirements-
• Median barriers are required if median width is less than 5 m.
• Minimum width is limited to 1.5 m.

2. Problems Associated-
• Traffic restriction if broken, causes congestion as well.
• Pedestrian accidents if uncrossable barriers are provided.
• Broken medians act as median openings.
increasing the chance of collision.
Improvements-
• Proper maintenance of ends and broken medians.
• Material used for barriers should be impact absorbing.
• Clear visibility must be provided at median openings.

3. Kerbs
Functions-
• Facilitates drainage.
• Lateral support to the pavement.
• Discourages the drivers to drive on sidewalks and footpaths.
• Improves aesthetic appearance.
General Requirements-
• Reveal portion varies from 10cm to 20 cm.
• Decided from topography present at the road site.

4. Problems Associated-
• If breaks, it becomes starting point for pavement deterioration.
• Material cost, problem can not be solved.
• Blockage of drainage hole.
 Improvements-
• Proper maintenance.
• Adequate support to the kerbs.
• Proper cleaning of drainage holes.

5. Median Gaps
Functions-
• Provides refuge area for pedestrians.
• Provides opening to change the lane for vehicles.
 General Requirements
• Opening must be there at an interval of 1.5 km (NH) and 2.0 km (Expressways) in order to separate the damaged vehicles from
carriageway.
• Opening width should be limited to 18 to 20 m .
• Projected median portion at opening should be curved.

6. Problems Associated-
• Chances of collision of vehicles on the opening.
• Pedestrian accidents may occur.
• Congestion due to domination of local traffic.
Improvements-
• Limit the number of openings.
• Proper designing of opening-
Bullet nosed shape for Right turning traffic,
Semi-circular shape for U-turning traffic.
• Maintenance of broken corners and projected part.
• Restriction to local traffic.