Mayor de Blasio’s newest rationale for his deal to shutter the horse-carriage stables in the West 50s is that it will alleviate traffic congestion in Midtown. At an MLK Day event yesterday in Brooklyn, the mayor told reporters:

The value we’re getting here for the people is to address the congestion issue, again when the horses are coming from the West Side to Central Park, to address the congestion issue along all the routes that the horse carriages ply, to address the safety issue, because there have been a number of crashes. I think it’s a good long-term investment to get the horses off the streets.

Yet carriage traffic on the streets between the stables and Central Park now makes up such a tiny share of overall vehicle travel that eliminating it would barely register on the traffic meter. There are a mere 68 carriages, and each travels around five miles a day (that figure assumes that each carriage makes one to two 3.2-mile round trips daily between its stable and the park). Total daily carriage-miles traveled, or CMT, is around 340 miles.

By comparison, cars, taxis, trucks and buses rack up 3.3 million vehicle miles traveled (VMT) each weekday in the Manhattan Central Business District. Against that figure, the 340 miles of CMT are just one part in 10,000.

That ratio would shrink by three if we limit the comparison to Midtown, which occupies the northernmost one-third of the CBD. We could also charge each horse carriage with several times the traffic impact of a taxicab or car, due to larger size and lesser maneuverability. But even accounting for those factors, shutting down horse-carriage traffic still leaves in place the equivalent of at least 999 of every 1,000 vehicles on Midtown streets.

The projected average traffic gain for Midtown is one-tenth of one percent Averaged across the entire CBD, the improvement shrinks to three-hundredths of one percent. The CBD average traffic speed of 9.000 mph becomes 9.003. Vehicle-hours stuck in traffic fall by an imperceptible 100 per day.

As for the mayor’s other newly voiced concern, crashes, I recently computed crash rates for carriage horses on Midtown streets over a five-year period (mid-2009 to mid-2014) and compared them to crash data for motor vehicles in the NYPD’s 18th PCT, Midtown North. I found that carriage horses traveled an average of 20,300 miles on city streets between reported “incidents,” whereas motor vehicles in midtown traveled 16,800 miles between reported collisions.

That is, carriage horses were involved in 17 percent fewer traffic incidents than motorists for the same distance covered on the same streets. These figures suggest that, per mile traveled, carriage horses are at least as safe to their patrons, handlers and other road users as are motor vehicles.

“I think anyone who drives in New York City — data’s great, human experience is great too. I drove plenty of times behind those horse carriages,” Mayor de Blasio told reporters yesterday. “And we’ve all seen the crashes and what they did to the people involved and the horses involved. This is a no-brainer: they don’t belong on the streets of the city.”

Speaking of human experience, just yesterday I had to halt my bicycle on a frigid side street while a shopper finished loading her groceries into a double-parked Uber. And last week I lost precious seconds while fellow straphangers exited and entered my subway car. Imagine!

Decisions that will impinge on the livelihoods of hard-working New Yorkers who drive horse carriages (and pedicabs) need to be made on a broader base than individual irritation. The city just spent two million bucks on a Midtown traffic study. Why not apply that here?

The traffic and crash findings here are derived in Komanoff’s Balanced Transportation Analyzer spreadsheet [Excel file]. Go to Index (second tab) and click on the link to the “Horses” tab near the bottom of the list.