Post #521: The cost of sidewalks

Posted on January 31, 2020

Source:  Google maps.

The point of this post is pretty simple:  The cost of installing new concrete sidewalks various enormously.   And the cost of the sidewalk itself — i.e., the 5′-wide ribbon of concrete — is the least of it.  The bulk of the cost is in everything else that has to be done — curb, gutter, curb cuts, ramps, and, most importantly, drainage including storm sewers.

To make this point, I identified four sidewalk projects in the Town of Vienna, and estimated cost per linear foot.  (Detail given below.  This is a “sample of convenience”, being the first four projects I ran across.)  The costs were $100, $150, $445, and $666 per linear foot of sidewalk.  Presumably, if I’d looked at a larger sample of projects, I would have seen even more variation.

In the Town of Vienna, a) there’s really no meaningful “typical” cost for putting in sidewalks and b) in any given situation, the cost might be a lot more than you’d think.

The high costs of sidewalks — and the fact that literally “the sidewalk” is typically the smallest part of the cost — has some important implications for a couple of items that I’ve mentioned recently.

Robinson bequest for sidewalks.  At the last Transportation Safety Commission (TSC) meeting, I found out that the Robinson estate bequest for sidewalks in the Town of Vienna was being interpreted as literally that:  payment for the concrete sidewalk, period (Post #518).  Depending on the project, then, the Town would have to pay for everything else to make that sidewalk possible.  That’s certainly going to tilt the use of those funds toward simple projects where (e.g.) there is already curb and gutter in place, with no need for extensive modifications for site drainage.

Sidewalks versus road closure for the neighborhoods behind Sunrise/444 Maple West.  At the last Town Council meeting, citizens offered some things the Town could do to address pedestrian safety and traffic in the neighborhoods adjacent to the proposed Sunrise facility (Post #517).  Among those was the idea of putting in sidewalks on (among other) Glen Avenue.  But Councilman Potter suggested that simply closing Wade Hampton at Glen would be a less costly solution.  And based on these per-foot costs, that seems like a plausible statement.  Based on those four costs per foot, 1400′ of sidewalk for Glen Avenue (pictured above) might cost anywhere from $140,000 to more than $900,000. 

Baseline via VDOT

First, as a baseline, I found a reasonably recent set of estimates (.pdf), done for the Virginia Department of Transportation (VDOT), showing typical construction costs in our area.   They say that the typical cost of plain-vanilla 5′ wide sidewalk, plus curb and gutter, runs about $70 a linear foot.  Plus a bit of excavation.  That’s $30 for the concrete sidewalk, and $40 for the curb and gutter.

But the cost of the sidewalk, in isolation, is not the cost of the project.  For example, according to that source, every new Americans With Disabilities ACT (ADA)-complaint curb ramp typically adds about $2500 to the cost.  (So a ramp costs as much as 35′ of plain-vanilla sidewalk, curb, and gutter).  And dealing with drainage — regrading the adjacent land, installing storm sewers and the like — can cost several times what the sidewalk itself costs.

Four actual Town of Vienna project costs

I’m just going to show the first four examples that I ran across, comparing the Town’s cost estimate to the length of the sidewalk per Google Maps.  These are cases where the project was described as a sidewalk project (e.g., not rebuilding the associated roadway or anything like that).

Here’s 836 Ninovan Rd SE, $36,000 for what appears to me to be 87′ of sidewalk, curb, gutter (as measured from Google maps), or about $425/foot.  That was clearly flat, level ground.

Here’s west side of Nutley, filling in the gap between the shopping center and Windover Heights, $100,000 for what appears to be about 150′, or about $666/foot.

On the other hand, Cottage street, $241,500 for what appears to be 2225 feet of sidewalk, or just over $100/foot.  You can look at it in Google maps and see this was straightforward.

On 300 and 302 Adahi, $28,000  for about 190′, or $150/foot.  This one was described as easy enough that it didn’t need site plans.