JOIN USSix-lane, elevated high speed roads converging at two-lane junctions; intersections at curves; median cuts to serve private interests… Poor road engineering is Bengaluru’s bane, its design nightmare, a sure-shot recipe for disaster on the move.
The defects are in-your-face, glaringly obvious. Studies have repeatedly shown how they trigger accidents galore, spark traffic chaos and turn every traffic management plan upside down. Is there a way out? Can a belated course correction have the desired effect?
A recent traffic police-commissioned study by SLS Transport Training Institute has clearly identified the engineering defects.
Frequent curves
Here’s one finding: “Frequent curves and changes in gradient have been associated with accident spots. The main roads are found to have deep curves and the minor roads have curves at the intersections with major roads, thereby seriously affecting safety.”
The variation in road gradient is a city-wide defect. That most accident black spots are associated with it is proof enough of how dangerous it can get for motorists and pedestrians. Gradient change at intersections puts complex demands on the skills of the drivers. This get particularly tricky while taking right turns.
Inconsistent carriageway width has been cited as the single most critical cause for traffic bottlenecks. A direct result is the funneling effect, where a much wider road narrows down triggering heavy traffic build-up. This, in turn, sparks a cascading effect on the other roads in the vicinity.
Additional Commissioner of Police, Traffic, M A Saleem draws attention to the six-lane Airport road that narrows to two lanes on Hebbal flyover. “It is important to maintain the uniform width of the road throughout, before and after a junction. When junctions are too close to one another, the problem of varying width gets amplified,” he explains.
Lane uniformity
To tide over this recurring issue, many roads in the Central Business District (CBD) were made one-way. This did work for a few years. But the explosive vehicular growth has put immense pressure on even the widened one-way roads.
This is why the design of TenderSURE roads has a high thrust on lane uniformity.
Consistent lane width, as urban mobility expert V Ravichander points out, depends a great deal on the Right of Way (the distance from compound wall to compound wall on a road). Good road design is built around the minimum RoW. The implication is clear: The effective uniform width of a road is the width where its RoW is the minimum. “If the minimum RoW is 28 metres, at the point where it goes up to 35 m, seven meters become available for parking, bus stop or other utilities.”
Surface milling is another critical need before a road is re-asphalted. But it is an alien concept in the City. “We don’t do it. Instead, we tend to patch up the roads and apply tar on tar, rising the road height. To provide for future increase in height, the footpaths are now raised very high. This is a terrible piecemeal approach,” feels Ravichander.
Surface milling
To ensure longetivity, the TenderSURE road approach is to first clean up the surface through milling and ensure that the road geometry is right, both in terms of height and a slightly raised centre. This ensures that the water is drained out to the shoulder drains.
“Water is the biggest enemy of asphalt. Today’s puddle is tomorrow’s pothole.
TenderSURE roads are designed to drain out rain water in 20 minutes.”
Bengaluru has about 13,000 km of road, of which 800 to 1,000 km are key roads. Ideally, Ravichander feels, at least the key roads should be upgraded under TenderSURE for which the State government has set aside about Rs. 500 crore.
However, upgrading the entire 500 km length of arterial roads would require an estimated Rs 5,000 crore.