Why is there less road traffic on Fridays?

October 16, 2009 6:54 AM

Why is there less road traffic on Fridays?

I commute to work at roughly the same each day and have noticed a significant and consistent drop in traffic on Fridays. If I were to guess I would say the roadways are 20-30 percent lighter in the mornings between 8 and 9. This is on a major thoroughfare in the Boston suburbs (Route 2 East) going into the city and is consistent enough to be predictable.

Is this a common phenomenon or just some local statistical blip?

First thoughts: Lots of people have 4 day work weeks? College students don't have classes on Friday? I really have no idea.

posted by jeremias to travel & transportation (23 comments total)

I experience the same thing in NJ (and I love it - it makes my commute a tad more tolerable if I can look forward to less stress on Friday mornings). When I take a day off, I always take a Friday to make a three day weekend. I think a lot of people do the same thing.
posted by Nutritionista at 7:02 AM on October 16

A lot of people I know work from home one day a week and Friday is a popular one for that.
posted by caddis at 7:02 AM on October 16

I just wanted to chime in to say I do not believe this local to just you, this happens where I live also. I commute from Raleigh, NC to Chapel Hill 5 days a week and M-Th it takes often more than 45 minutes to get where I am going but on Friday I can often get there in under 30 minutes.

And YET...the Friday drive home at 5 seems more congested than ever!
posted by ejazen at 7:02 AM on October 16

I take the Mass Pike westbound to work, and I haven't noticed this at all. Jealous.
posted by oinopaponton at 7:03 AM on October 16

4 day work weeks or 9/80 schedules where you get every other Friday off. When you do a 9/80 your Friday at work is also an 8 hour day instead of 9, so people might be coming in at different times than normal.
posted by IanMorr at 7:03 AM on October 16

At my workplace approximately 15-20% of people work from home on Fridays, logged in remotely via Citrix. It's a good way of keeping a happy workforce. People have a day less commuting, and their weekend starts earlier because they don't have the journey home.
posted by essexjan at 7:11 AM on October 16

Like essexjan, most people in my workplace work at home on Fridays via Citrix. (Actually, at my workplace, about 1/3 people work at home on Mon, Wed, Fridays, and the rest - like me - work at home 100% but I am super-lucky).

If you go into my workplace on a Friday there are like, two people there.
posted by gaspode at 7:13 AM on October 16

Ah, the good old "Friday light". It's a combination of (more) people taking three-day weekends and (less) people working 9/80s.
posted by Gridlock Joe at 7:14 AM on October 16 [1 favorite]

I take the train to work. The train station parking lot, and the train itself, are also less crowded on Fridays. I'm sure it's not just a timing difference where people are going in later, because when I go home in the evening, there aren't cars parked in the aisles, on the grass, on the pedestrian walkways, like there are every other day of the week.

The office I work at is also somewhat deserted today (Friday). We don't have 4-day work weeks or 9/80 schedules at this time of year. What seems to happen is if people are going to take a single day off, it's going to be a Friday (or, less popularly, a Monday) so they can have a long weekend.

Road traffic does indeed seem to be far worse on Friday evenings, though, both in the city where I work, and in the suburbs where I live. It seems to be the one day of the week when everyone wants to leave work on time. Fridays before long weekends are particularly hellish.
posted by FishBike at 7:16 AM on October 16

We too have a lot of people either doing a compressed work week (4 days x 9 1/2 hours) or just doing a shorted week (4 days x 7 1/2 hours). Mondays and Fridays are the most popular days to take off, of course. There are even a few people doing highly compressed weeks: 3 days x 12 hours on a rotating schedule so that there's 7 day coverage (in two shifts) in certain high-availability labs. They get paid extra for having weird schedules, even.
posted by bonehead at 7:18 AM on October 16

Friday also seems like the most common day for people to take off for leisure reasons, which should have some impact in the aggregate.
posted by 6550 at 7:20 AM on October 16 [1 favorite]

I know people who also seem more likely to get "sick" on a Friday (or Monday, or rainy day).
posted by mokeydraws at 7:24 AM on October 16

Not only does just about my entire company work from home on Friday, but we recently started reaching a critical mass where people who don't care about working from home do so anyway, because the office itself is a ghost town. In fact, I'm typing this from my sofa, while some work compiles.
posted by Tomorrowful at 7:30 AM on October 16

It also depends on where you live. Afternoon traffic during summers in Minneapolis-St. Paul is a bit heavier because a lot of people have cabins outside the metro area. True they might take Friday off (at least a half day), but they've replaced commuting to work with an SUV hauling a boat to the lake.
posted by nathan_teske at 7:39 AM on October 16

I'm reaching back to my grad school days a bit, so my memory may not be 100% correct here. I no longer do transportation work. But anyway...

Peak-hour traffic counts are usually done Tuesday-Thursday because Monday and Friday counts are really unreliable and vary a lot depending on time of year, location, etc.

It may be that in Boston there are people leaving directly from work to points north and south on the weekends, for vacation or whatever, while on weekdays they go home to the western suburbs. Who knows.

There's also going to be a lot more variation in when people arrive/leave work on a Monday/Friday. Maybe they're coming in from out of town and arrive later in the morning on Monday, or maybe on Friday half the people leave an hour early. A flattening/widening of the peak hour to, say, two hours, can have a HUGE impact on how busy the road is. For example, Saturday is (IIRC) the most heavily traveled day of the week, but the travel is more spread out over the course of the day so it doesn't seem that way. When a road is operating close to its capacity, adding even 5% more cars can cause it to stop flowing freely.

The short version is that Friday is a spooky day for people who do traffic analysis. A bazillion different things could be going on to make things better or worse than normal.
posted by paanta at 7:49 AM on October 16 [1 favorite]

I'm with ejazen (I live between DC and Baltimore) and the mornings are light, but the drive home is probably the longest on a friday. I blame all the people playing hooky trying to get a jump on the weekend festivities... come on! You already had the day off, wait until rush hour is over... I'm wearing work pants here!
posted by syntheticfaith at 7:51 AM on October 16

Same here in Denver. Traffic is great for me on Fridays, but I don't take the freeways. I have noticed that the busiest traffic shifts an hour earlier--probably because people are most likely to leave early on Fridays. (I have a friend who has a 37 hour work week and always gets to leave early on Fridays.)

In the winter we usually have to eat lunch within walking distance or at the cafeteria because if we drive anywhere there will be no place to park when we get back. On Fridays, it's never a problem so my co-workers and I always think of Fridays as fun lunch day.
posted by Kimberly at 7:59 AM on October 16

I'm on Route 2 West in the mornings, so we're passing each other (hi!).

Most people who do have 4-day work weeks tend to take (or are told to take) Fridays off. Same with 3-day work weeks.
I would also guess that a lot of the tech companies in Cambridge and along the I-95/128 loop employ the 9/80 schedule or a work-from-home Friday, which would be a more anecdotal reason for your particular commute schedule.

I do not think colleges have anything to do with it; most students live on/next to campus.
posted by Sprout the Vulgarian at 8:16 AM on October 16

At my workplace we usually schedule half a day for everyone in the team, except for one who covers in the afternoon. This allows people to take care of weekday personal business, and get the weekends started a little early. This means that the Friday afternoon drive home is a little easier for the rest of us, who work all day.

On the Friday prior to the start of hunting season, on Saturday, there is always a traffic jam in the afternoon on the way out of town (Houston), as people are rushing to their hunting leases.
posted by Midnight Skulker at 8:21 AM on October 16

So it sort of looks like the 4 day work week/tele-commuting factor seems to be the consensus, possibly combined with other Friday factors.

I just had no idea the numbers of people in this category would be so large. It seems like there is a significant trend here that I wasn't aware of. This is also the first time I've ran across the "9/80" concept for some reason. Interesting.
posted by jeremias at 9:01 AM on October 16

Also, I concur that the ride *home* on Fridays is the reverse, almost always extremely busy. This has always seemed logical though since you would be adding the number of people exiting the city for the weekend to the number of normal commuters going home.
posted by jeremias at 9:08 AM on October 16

My evening commute homeward homeward takes me toward the city, and it is longest on Friday's.
posted by NortonDC at 9:19 AM on October 16

mokeydraws writes "I know people who also seem more likely to get 'sick' on a Friday (or Monday, or rainy day)."

About 40%?

jeremias writes "I just had no idea the numbers of people in this category would be so large. It seems like there is a significant trend here that I wasn't aware of."

Like paanta said when a road is loaded to capacity or over capacity a very small difference in the number of cars traveling the road can make a huge difference in how well it flows. A couple of percentage points can mean the difference between well flowing freeway and grid lock.
posted by Mitheral at 12:10 PM on October 16