4500 cars a day on a freeway - is this a low traffic count?

[bugo]

The traffic counts on the Creek Turnpike north of 11th Street are less than 4500.  Is this low for a 4 lane freeway?

[hotdogPi]

If it's an urban area, yes. MA 213 is 45000 per day, which is 10 times as much, and it's 30 miles from Boston. It is 2 lanes in each direction. It connects 2 Interstates. MA 213 is 3 and a half miles long.

[J N Winkler]

The traffic counts on the Creek Turnpike north of 11th Street are less than 4500.  Is this low for a 4 lane freeway?

It is, in fact, too low to justify widening to four-lane divided, by the traditional criterion (10,000 VPD in flat country, dropping to 5,000 VPD in steep mountainous terrain), let alone development to full freeway standard.

[Alps]

4500 per HOUR is what I'd expect to see on a 4 lane freeway during rush hour in a metro area.

[bugo]

This stretch of road is always dead.  I've never seen more than a few cars on this section, and there is zero congestion.  This road is grossly underutilized (it is a far better route than I-44 through Tulsa, although it is a bit longer.)

[froggie]

4500 per HOUR is what I'd expect to see on a 4 lane freeway during rush hour in a metro area.

Which is more or less the upper end of capacity for a 4-lane freeway.

[hotdogPi]

4500 per day is about 1 per 20 seconds.

In mid-New Hampshire, on I-93 (about exit 28), it's 4 lanes, and I seemed to pass a car on the other side about every 6 seconds. Multiply by 2 (we were moving too), and it's about 12 seconds per car. Of course, since this is a two-digit interstate, it's four lanes. Unlike I-93 in Massachusetts, there were very few trucks.

Comparison:
OP: 4500 per day, 20 seconds per car.
MA 213 (mentioned earlier): 45000 per day, 2 seconds per car.
I-93 in NH: 8000 per day, 12 seconds per car.
I-88 in New York: 12000 per day, 8 seconds per car.
MA 28 north of Boston (not a freeway): 12000 per day, 8 seconds per car.

The last three are estimates.

[froggie]

You're assuming that it's a consistent flow throughout the day (and night).  That just isn't the case anywhere.

[Rick Powell]

The traffic counts on the Creek Turnpike north of 11th Street are less than 4500.  Is this low for a 4 lane freeway?

I live in IL which probably has the most extreme variation between freeway volumes within the state.  The Dan Ryan has 303,000 vpd around 35th street in Chicago, while I-180 west of Hennepin has about 2,600 and I-72 west of Jacksonville goes as low as 5,500.  Some of the 4-lane expressways go low too, with IL-336 northwest of Quincy as low as 3,000 in some sections and US 67 south of Roseville around 3,800.

[BigMattFromTexas]

As of 2008, Houston Harte Expwy got 39,000 a day.. I'm sure this is up to 45,000 a day due to the crazy oil boom here, but 4500 seems really low. Also Angelo is <100,000 in population.
BigMatt

[Scott5114]

What is the cutoff where a full freeway is usually justified? AADT numbers for SH-9 in Norman (which is expressway, four lane divided with stoplights at major intersections and no other access, speed limit 50 MPH) are 27600—29200.

[froggie]

What is the cutoff where a full freeway is usually justified? AADT numbers for SH-9 in Norman (which is expressway, four lane divided with stoplights at major intersections and no other access, speed limit 50 MPH) are 27600—29200.

Highly variable, depending in part on the number of access points, crash rates, and (in the case of signalized intersections) intersection throughput.

Regarding signalized expressways such as your OK 9 example, you can have pretty good flow at high traffic levels if you have both decent signal timing AND signal spacing.  MN 55 out of Minneapolis to the west isn't too bad in this regard, and MnDOT has also put a lot of money into a coordinated signal system on MN 65 through Anoka County.  DOTs can usually do a fully coordinated/connected signal system for an entire corridor for less cost than a single interchange project.

[J N Winkler]

What is the cutoff where a full freeway is usually justified? AADT numbers for SH-9 in Norman (which is expressway, four lane divided with stoplights at major intersections and no other access, speed limit 50 MPH) are 27600—29200.

Froggie is right--it is highly variable and, quite aside from any traffic-related considerations, the planning history of the road is a factor.  This is partly because it is much cheaper to upgrade an existing road into a full freeway when it has been planned for development to that standard from the beginning, with appropriate corridor preservation measures taken when land is still cheap.  In general, unlike the case with the 10,000-VPD rule of thumb for upgrading from two-lane to four-lane divided, the case for upgrading from one four-lane cross-section to another is highly dependent on the circumstances in a given case.

There are, however, some useful rules of thumb.  In a rural area you can expect the right-of-way cost of a freeway on new location to be around 10% of the construction cost.  In an urban area, you can expect right-of-way to be a substantial fraction of the total cost, if it is not actually larger than the construction cost.  For a typical freeway project, whether located in a rural or urban area, the benefit of accident losses forgone is usually a relatively small fraction of the benefits from time savings--usually around 25%.  And, finally, considered in isolation, grade separation as an alternative to a flat intersection design (signal or roundabout) can be justified for total volumes (on all approaches) as low as 20,000 VPD.  (Whether it is justified at a given intersection depends on how the volumes are balanced on the different approaches.  As an extreme, you wouldn't grade-separate for a RIRO with just a few dozen vehicles a day on the minor approach, which is the situation with the ranch entrances encountered on Interstates in west Texas and New Mexico.)

In Wichita, for example, Zoo Boulevard (which has never been on the state highway system) carries about 35,000 VPD, and in fact carries more traffic to the northwest of its interchange with I-235 than I-235 itself carries to the northeast.  The difference is that while I-235 was planned as a freeway from the beginning and built in the early 1960's when there was still very little development in its corridor, the maximum development that was ever envisaged for Zoo (aside from a brief moment in the 1950's when Patterns for Thorofares envisaged it as part of a freeway corridor that would have been very difficult to build even to contemporary standards) was as an urban arterial, and as a result its corridor is very built up with no prospect of inexpensive upgrade to full freeway.

The only major corridor in Wichita that has been successfully upgraded from urban surface arterial to full freeway is Kellogg Avenue, and that is partly because of some unusual circumstances.  First, Kellogg originally did not exist west of the Arkansas River, and the roadway that was built there comparatively late--probably in the late 1940's and early 1950's after site clearance in the late 1930's, initially under the name "Brockway Boulevard"--already had some freeway features, such as a divided cross-section, grade-separated interchanges at Edwards and Meridian (Seneca and Sycamore were added later as part of a new Arkansas River crossing), and stopping-up of nearly all minor street intersections.  East of the river, where Kellogg did exist, there was already a railroad grade separation by the time World War II started (the current viaduct is at least the third spanning the tracks between Emporia and Washington).  And further east, there were already service drives for a considerable proportion of the length, which facilitates upgrades since there is no pre-existing expectation of access and thus no taking of access rights involved.

[Henry]

If they weren't expecting a high traffic count, then why would they build the freeway in the first place?

[JREwing78]

Frequently, it's for continuity, "economic development", or "defense" reasons. For example, traffic counts on I-75 north of St. Ignace (in Michigan's Upper Peninsula) are pretty close to that 4500 vehicle-per-day figure. But it connects the rest of Michigan to Sault Ste. Marie (Michigan and Ontario), and it's an important (if not high-volume) border crossing.

If to highlight the seemingly overkill nature of I-75 in this area, US-2 west of St. Ignace has similar or higher traffic counts on a (mostly) 2-lane highway, as it connects the rest of the UP to downstate Michigan. In fact, they have enormous signs headed westward from St. Ignace reminding people US-2 is not a freeway (it's 4-lane with center turn lane for the first several miles westward).

What's unusual about the Creek Turnpike is the dearth of traffic on a freeway so close to a large metro area. I would imagine traffic counts would be considerably higher if there wasn't a toll there (though at under $3 a trip, it's not exactly expensive).

[Scott5114]

The Creek Turnpike is really riding the far outer rim of the Tulsa metro there. I would imagine there's not much of a reason for people living in Broken Arrow to head north to places like Claremore or east toward Chouteau with any regularity. My guess is that the vast majority of the people on the Creek at that point are bypassers.

[bugo]

The Creek Turnpike is really riding the far outer rim of the Tulsa metro there. I would imagine there's not much of a reason for people living in Broken Arrow to head north to places like Claremore or east toward Chouteau with any regularity. My guess is that the vast majority of the people on the Creek at that point are bypassers.

Most motorists who exit off at 31st Street have Pikepass.  Also, there is plenty of traffic from BA/Bixby/Jenks to Claremore and other towns on the I-44/US 66 corridor.

[Scott5114]

Also, there is plenty of traffic from BA/Bixby/Jenks to Claremore and other towns on the I-44/US 66 corridor.

Not saying there aren't some people that do that, just that it's likely to be random noise for most people rather than a regular trip of the sort that really drives AADT. (I know you work in that area–when was the last time you had a reason to go to Claremore?) From BA, you're most likely to go west along the Creek or northwest along the BA Expressway rather than north toward Claremore/Vinita/etc since there's no major population center along that corridor until Joplin.

[getemngo]

Frequently, it's for continuity, "economic development", or "defense" reasons. For example, traffic counts on I-75 north of St. Ignace (in Michigan's Upper Peninsula) are pretty close to that 4500 vehicle-per-day figure. But it connects the rest of Michigan to Sault Ste. Marie (Michigan and Ontario), and it's an important (if not high-volume) border crossing.

If to highlight the seemingly overkill nature of I-75 in this area, US-2 west of St. Ignace has similar or higher traffic counts on a (mostly) 2-lane highway, as it connects the rest of the UP to downstate Michigan. In fact, they have enormous signs headed westward from St. Ignace reminding people US-2 is not a freeway (it's 4-lane with center turn lane for the first several miles westward).

For reference, Chris Bessert has a photo of the sign:



And I-75 in Michigan gets a lot lower than 4500. From MDOT's 2011 AADT figures, it's 3500 at the Mackinac-Chippewa county line, and only 2800 just north of Kinross! That's not quite as low as I-180 in Illinois, but it's close. Wonder if that's the record low for a 2di, or at least for a "multiple of 5" Interstate? I bet, if I-73 ever comes to Michigan (and it would be paired with I-75 from Gaylord north), that will be the lowest for an Interstate concurrency. 

[english si]

Wonder if that's the record low for a 2di, or at least for a "multiple of 5" Interstate?

I-95 in northern Maine?

[getemngo]

Wonder if that's the record low for a 2di, or at least for a "multiple of 5" Interstate?

I-95 in northern Maine?

I stand corrected! AARoads' Interstate-Guide shows an AADT of 1880 between exits 62 and 63, and 2330 at the Canadian border. The data's over 10 years old, but it probably hasn't changed drastically since then.

I-15 is apparently 2700 from the Montana state line south through most of Clark County, Idaho... and of course, now I see there was a topic on this a year ago. My bad.

[NE2]

2011 NHPN data says I-15 north of Dubois, ID gets down to 2719 AADT, lowest non-Alaskan 2DI with data (other than what's probably an error on I-59 in Georgia). Actual year of measurement is unknown, but it jibes with ITD: http://www.itd.idaho.gov/highways/roadwaydata/counters/073/index.html (2951 in 2012)

[froggie]

2011 NHPN data

Which is actually 2002 traffic data, as I discovered when creating the Interstate traffic map for another thread.  It's listed in the metadata.