Uncategorized

Do pedestrian signals allow us sufficient time to cross a road?

February 24, 2019

author:

Do pedestrian signals allow us sufficient time to cross a road?

Strange as it may seem for most Indians, we are not expected to run, or even walk unusually fast, as we cross the road as pedestrians. In fact, pedestrian crossings must, by design, account even for the relatively slower movement of the elderly.

We know this is not the reality though, where a functioning pedestrian signal is uncommon, if not rare, and where one does exist, it fails to consider even the walking pace of younger people.

We wanted to understand just how much time pedestrians have to cross a busy road. And we turned our focus on to a road where multiple pedestrian accidents had been observed in 2017.

Consider a one kilometre stretch of Hosur Road, Bangalore. In particular, consider the traffic lights at Crossing 3 as marked in the map above, a few hundred metres away from NIMHANS Convention centre.

  • The cycle length here (sum of #1, #2 and #3, or #4, #5 and #6 in the image below) appears to be 100 seconds.
  • Of these 100 seconds, about 5 seconds (#1 or #4 or #7 in the image) are available for pedestrians to cross the road.
  • The remaining 95 seconds were dedicated to traffic moving on Hosur Road (#2 and #5), and traffic entering Hosur Road (#3 and #6).

 

Recommendations in Official Guidelines:

Are 5 seconds sufficient for pedestrians to cross this arterial road in Bangalore? IRC Guidelines (93: 1985) prescribe the following for pedestrian signals:

“The width of the carriageway to be crossed in metre may be divided by the assumed walking speed of 1.2 metre per second to determine the green interval required for the pedestrian to cross the carriageway.” – (i)

Further,

“A value of seven seconds must be added to this value (i) being the reaction time of the pedestrian and the total value will then be the green time that should be allotted for the pedestrian phase”. 

Going by the guidelines, the traffic lights in question here clearly do not provide pedestrians with the prescribed reaction time. More worryingly, however, it may be noted that the guidelines are not in use at all.

How so? Consider the width of this stretch of Hosur road to be 14 metres ,  as measured on Google Earth, since official records of the width have been hard to find online. If the road was 14 metres wide, the green interval to allow pedestrians to cross this road, as per the above-mentioned IRC guidelines, would be:

14 / 1.2 = 11.6seconds

The signal does not follow the IRC guidelines as it allows less than half this amount of time for pedestrians to cross the road.

Adding the prescribed reaction time of 7 seconds to the value derived above, the pedestrian signal time at Crossing 3 must be set to least 18 seconds, over thrice the current value.

 

International Case Studies

The pedestrian crossing time prescribed by the IRC guidelines (93:1985) are in line with international best practices aimed at balancing pedestrian safety and the movement of vehicles.

The United States Federal Highway Administration guidelines recommends dividing the crossing distance by 4.0 feet per second. The Americans with Disabilities Act guidelines recommends using 3.0 feet per second instead. Transport for London provides a table of pedestrian clearance time, which recommends a total of 15 seconds for a 14 metre road width, or 3.0 feet per second. IRC 93:1985 recommends 3.9 feet per second of green time.

 

What must Indian cities do?

The consensus worldwide is to allow sufficient time to cross a road at 3 to 4 feet per second, in addition to which our Indian guidelines recommends the provision of time for the pedestrians to react.

Considering the status quo, pedestrian crossing times in Indian cities must revise the clearance time and include a reaction time as recommended by the IRC guideliens. Please let us know your thoughts on Twitter (@thefootpaths) on whether or not this is feasible in major Indian cities, and why.

As for the junction on Hosur road studied here, as calculated earlier, pedestrians need to be allowed at least thrice the current clearance time should the city be serious about ensuring their safety.

Leave a comment

Your email address will not be published. Required fields are marked *