analyzing state highway mileage

[NE2]

I decided to do some analysis of http://www.fhwa.dot.gov/policyinformation/statistics/2013/hm10.cfm.

Nationally, 19% of public road mileage is state maintained. 15 states have more than this, of which at least seven have well-defined primary and secondary systems. (I'm not sure how Alaska works, and Wyoming may have an official primary/secondary split.)

You can see the data here and sort it by column (it's current sorted by percentage of total mileage): http://docs.google.com/spreadsheets/d/1g7Dwss3pL44pjLRd89AwKBW5fS2OBjy_64E8EEMgvX8/edit?usp=sharing

Some of the more interesting outliers:
Maine has the highest percentage without a separate secondary system. I don't know if they just have a lot of state routes, or if something else is going on (e.g. a bunch of unnumbered state highways).

Kentucky and Pennsylvania are the second and third highest (ignoring Alaska). Both have a lot of minor state highways. The same is true for Louisiana, but I'm not sure why New Hampshire is so high.

New Jersey has the lowest percentage, probably because it's so urban. Kansas is the second lowest, with a legislated policy of eliminating minor routes. I'm a little surprised by most of them near the bottom (I was expecting Arizona to be lower, but I suppose it doesn't have much in the way of total mileage).



Data on primary systems (which include Interstates and U.S. Routes) comes from:
Delaware: http://www.deldot.gov/information/pubs_forms/manuals/traffic_counts/2013/pdf/routes.pdf (I didn't bother eliminating overlaps, so it's a little higher than reality)
Missouri: anyone have the mileage? I can't find it
Montana: I forgot about this, but it's already so far down compared to the others
North Carolina: http://www.ncdot.gov/travel/statemapping/download/highwayroadmileage_2012.pdf (2012 data)
South Carolina: https://www.masc.sc/SiteCollectionDocuments/Getting%20To%20Good%20for%202-13-13%20Municipal%20Assn.pdf p. 4 (2012 data)
Texas: http://www.txdot.gov/apps/eGrants/eGrantsHelp/Reports/HSPP_FY13.pdf p. 26 (2010 data?)
Virginia: http://www.virginiadot.org/about/vdot_hgwy_sys.asp (not 2013 data)
West Virginia: http://gis.wvdot.com/gti/GISTemplates/HPMS_Reports/Rdwy_Stats_2013.pdf (not sure why the total doesn't match the FHWA figure)

[Duke87]

Define "separate secondary system". Pennsylvania certainly has one, the quadrant routes. But aside from reference markers they aren't signed. If Delaware counts as having a separate secondary system, Pennsylvania certainly does too.

As for New Jersey, it being generally urban isn't the only thing. New Jersey does have a conspicuously lean state highway system compared to surrounding states, but instead it has a ton of county routes. A lot of roads that would be state highways in other states are county routes in New Jersey.

[NE2]

Define "separate secondary system". Pennsylvania certainly has one, the quadrant routes. But aside from reference markers they aren't signed. If Delaware counts as having a separate secondary system, Pennsylvania certainly does too.

Pennsylvania groups everything into one system, but gives some of them signed numbers. The "quadrant routes" are merely the state-maintained highways that do not currently have signed numbers; before 1987, there was no difference in legislative route numbering between the signed and other routes. It may be that Delaware does something similar (since the signed routes do have road numbers), but at least Pennsylvania doesn't maintain residential subdivision streets like Delaware does.

[slorydn1]

Thanks for that NE2.

I had often heard that NC had the second highest total of state maintained mileage in the country but that is the first time that I had seen it in tabular form.

The running joke among us here is that if you can drive on it without the need for 4 wheel drive and mud tires it's state maintained. Of course that is most certainly not accurate, but it feels like it sometimes.

Technically I don't actually live in New Bern, I actually live in River Bend which is its own little town just SW of New Bern. The main road in and out of River Bend (Shoreline Dr) is state maintained, but all of the side streets off of it are maintained by the HOA's of the various streets. It's pretty much the same deal in Fairfield Harbor, Stately Pines, Carolina Pines (etc.), with one main road in/out is maintained by the state and the HOA's take care of the side streets.

Any road that actually takes you somewhere is state maintained around here, though.

[Mapmikey]

Virginia's totals from 1918-2013 for various categories that are included in all this data can be found here: http://www.virginiadot.org/VDOT/Projects/asset_upload_file855_5535.pdf

Mapmikey

[Zeffy]

New Jersey has the lowest percentage, probably because it's so urban. Kansas is the second lowest, with a legislated policy of eliminating minor routes. I'm a little surprised by most of them near the bottom (I was expecting Arizona to be lower, but I suppose it doesn't have much in the way of total mileage).

Northeastern New Jersey is urban, but most of the state is suburban or rural in the case of most of Sussex and Warren counties.

As for New Jersey, it being generally urban isn't the only thing. New Jersey does have a conspicuously lean state highway system compared to surrounding states, but instead it has a ton of county routes. A lot of roads that would be state highways in other states are county routes in New Jersey.

Yup, 5xx county routes here are the equivalent of secondary state highways. They follow a state-wide numbering scheme but instead are maintained by the county and not the state. I actually like it like this; it gives you a good clue on whether or not you should expect it to be plowed and whatnot compared to the other state roads. My county does a good job at it. Others... well...

[hotdogPi]

but I'm not sure why New Hampshire is so high.

(This will also partially explain why Maine is on top.)

Except for places inside or just outside major cities, almost all important roads are numbered. At least 75% of towns in New Hampshire contain an intersection of two or more routes^{[citation needed]}. In addition, north of Franconia Notch, there are very few roads at all, and the roads that do exist will increase the percentage because most of them are numbered.

Most towns in New England have an intersection of two or more routes. It is not just New Hampshire and Maine. However, while route mileage is about the same in a specified amount of area, Massachusetts, Connecticut, and Rhode Island have more unnumbered roads.

Also remember that routes in New Hampshire sometimes have A after the number, more than in most other states (e.g. 3A, 28A, 107A).

[hbelkins]

Kentucky doesn't differentiate by route marker, other than the traditional Interstate-US-state signs, but it definitely classifies roads into four systems: state primary, state secondary, rural secondary and supplemental. Rural secondary is special because state law designates a certain percentage of road fund expenditures for each county to go to the RS system.

[yakra]

Maine has the highest percentage without a separate secondary system. I don't know if they just have a lot of state routes, or if something else is going on (e.g. a bunch of unnumbered state highways).

A bunch of unnumbered state highways.

Maine has state highways, state aid highways, and townways. State highways and townways are exactly what they say on the tin. State aid highways have funding/maintenance/responsibility split up between the municipality and the state. In the winter, the township is responsible for snow clearing and related maintenance (Title 23, §1003), with the remainder of maintenance assumed by MDOT (Title 23, §802).

Numbered state routes can and do use both state highway and state aid alignments, often switching between the two. I know of only two instances of a numbered state route on townway.

WRT the tables in the OP:
8378 miles (NE2, how did you arrive at figures 0.2 miles less than what the FHWA has listed? o_O) seems way high for state highways alone, but a bit low with state aid highways included. Wonder how it was calculated; right now leaning toward including all the state aid highways. Also, would both carriageways of divided highways (EG, I-95 north and south) be included?
I could, theoretically, write a program to crawl the shapefiles and come up with some mileage figures. But that's more effort than I want to put into answering the questions right now.

Kentucky and Pennsylvania are the second and third highest (ignoring Alaska). Both have a lot of minor state highways. The same is true for Louisiana, but I'm not sure why New Hampshire is so high.

So, PA would be 3rd for the states without a separate secondary system. Noting that this would also include a bunch of unnumbered state highways, or those with just the little white markers and no keystone-style sign.

NH apparently internally has primary and secondary state highway systems. The primary system includes the interstates, mainline US routes (US302 Business, recognized by AASHTO but signed only as NH16A, is secondary), the Everett Turnpike and Raymond Wieczorek Drive (the Everett Tpke - MHT connector), and important state routes (EG, 9, 101, 12, etc.); a quick look around the shapefiles doesn't suggest anything else unnumbered other than ramps to/from other primary hwys. While I don't know anything about funding/maintenance between state & municipalities in NH's case, these secondary highways are similar to ME's state-aid hwys in that they're frequently part of numbered state routes, which can also jump between being on the primary & secondary systems, and there are also a significant number that aren't part of a numbered, signed state route. So, the primary/secondary distinction is not visible to Joe Motorist, to whom State Routes is State Routes.

[kurumi]

It's striking how few state highways California has compared to Florida and Texas, two states that resemble it based on population and open space. NE2's analysis quantifies this.

Even breaking down similar urban areas (SF Bay vs. Miami to West Palm Beach) -- seems like the latter would have 3x to 5x more numbered highways.

[NE2]

Miami is special as the only county that got more state roads in the 1980s.

[Scott5114]

Kentucky doesn't differentiate by route marker, other than the traditional Interstate-US-state signs, but it definitely classifies roads into four systems: state primary, state secondary, rural secondary and supplemental. Rural secondary is special because state law designates a certain percentage of road fund expenditures for each county to go to the RS system.

Are these designated by route, or can a route jump between classifications?

[NE2]

Kentucky doesn't differentiate by route marker, other than the traditional Interstate-US-state signs, but it definitely classifies roads into four systems: state primary, state secondary, rural secondary and supplemental. Rural secondary is special because state law designates a certain percentage of road fund expenditures for each county to go to the RS system.

Are these designated by route, or can a route jump between classifications?

A route can jump, much like federal aid systems.

[Revive 755]

Missouri: anyone have the mileage? I can't find it

Try here.

It seems Missouri likes to frequently change what is considered primary and secondary.

[J N Winkler]

New Jersey has the lowest percentage, probably because it's so urban. Kansas is the second lowest, with a legislated policy of eliminating minor routes. I'm a little surprised by most of them near the bottom (I was expecting Arizona to be lower, but I suppose it doesn't have much in the way of total mileage).

I have a slightly different explanation for Kansas.  It is in the top five for total public road mileage (at about 134,000 miles) because it is a medium-large state (100% PLSS) in which virtually every county section line is covered with a designated public highway, even if it sees very little traffic.  As a result, a state highway system legally capped at 10,000 miles is a very small fraction of the total mileage.  Arbitrage under the cap has amounted to just a few hundred miles over the past decade or so.

Kansas does have some very long paved county roads, straddling multiple counties, that in other states might very well be part of statewide signed secondary, supplementary, or county trunk highway systems.  As an example, the highway known as Ridge Road in Wichita is paved almost all the way from northern Sumner County to southern Saline County, a distance of almost 100 miles in five counties (it has a break where the airfield of the Wichita airport covers the relevant section line).

I haven't investigated to see how common statutory system mileage caps are.  Kansas often gets called out on this forum as an oddball for having such a cap, but Indiana apparently has one as well.  I suspect there are many others.  In states where the top transportation official has the discretion to designate highways, as is the case in Kansas, it is a convenient way of ensuring trunk value for any state highways beyond the minimum needed to furnish NSWE connections among the county seats.

[hbelkins]

Kentucky doesn't differentiate by route marker, other than the traditional Interstate-US-state signs, but it definitely classifies roads into four systems: state primary, state secondary, rural secondary and supplemental. Rural secondary is special because state law designates a certain percentage of road fund expenditures for each county to go to the RS system.

Are these designated by route, or can a route jump between classifications?

A route can jump, much like federal aid systems.

Once upon a time, a section of US 62 in Mason County was designated as "supplemental," the lowest of the four classifications. That's since been changed.

The full state map shows primary routes in red and doesn't do a really good job of differentiating between the other three classifications, but the individual county maps available online show them in different colors.

[NE2]

Missouri: anyone have the mileage? I can't find it

Try here.

It seems Missouri likes to frequently change what is considered primary and secondary.

I was looking for data on the lettered vs. numbered routes. Your link is some austerity crap that omits many numbered routes.

I haven't investigated to see how common statutory system mileage caps are.  Kansas often gets called out on this forum as an oddball for having such a cap, but Indiana apparently has one as well.

Nah, Kansas is the oddball for requiring state highways to be given to cities if the cities annex the entire thing.

[Duke87]

Kansas and Indiana are the only states I know of where mileage caps have ever forced the elimination or realignment of a route. It is possible that other states may have statutory caps which they aren't close to hitting and therefore we don't see any effect from it.

It's also worth noting that in many states (e.g. California) the DOT itself does not have the authority to add or remove roads from the state system, it is defined specifically by legislation what the state maintains.

[NE2]

Kansas and Indiana are the only states I know of where mileage caps have ever forced the elimination or realignment of a route.

Are you sure about this? It's often claimed that INDOT got rid of surface roads inside I-465 due to the cap, but there's enough leeway that this is bull.

[Duke87]

I seem to recall it coming up in a discussion of US 40 being realigned onto I-70 in Terre Haute that a mileage cap was the reason why. But I have not heard this from an official source. Seeing as we have a lot of people who love to treat speculation as fact it should be taken with a grain of salt.

Indiana's cap is 12,000 miles, they currently maintain 11,175 miles per the FHWA data. But for the purposes of enforcing the cap it's the state's bookkeeping that matters, not FHWA's. Per INDOT's own website they have 11,169 centerline miles of state highway, but they also note that they have 658 centerline miles of ramps. Add the two together and you get 11,827. Which leaves little slack, if ramps are counted against the cap. The relevant statute does not precisely define how the miles are to be measured:

IC 8-23-4-2 State highway system; designation; composition; selection criteria; classification
Sec. 2. (a) The state highway system shall be designated by the department. The total extent of the state highway system may not exceed twelve thousand (12,000) miles. The state highway system consists of the principal arterial highways in Indiana and includes the following:
   (1) A highway to the seat of government in each county.
   (2) Connecting arteries and extensions through municipalities.
(b) In determining the highways or sections of highways that are a part of the state highway system, the department shall consider the following:
   (1) The relative importance of each highway to county or municipal government.
   (2) Existing business and land use.
   (3) The development of natural resources, industry, and agriculture.
   (4) The economic welfare of Indiana.
   (5) The safety and convenience of highway users.
   (6) The financial capacity of the state to reconstruct, construct, and maintain the highways selected to desirable standards.
(c) The state highway system shall be classified for purposes of management, establishment of standards, and priority for use of funds and resources. Classification of the system may conform to the department's designation of the state's federal aid system.

[NE2]

If ramps are counted, dual carriageways should be double counted. Which certainly doesn't happen.

[The Nature Boy]

Thanks for that NE2.

I had often heard that NC had the second highest total of state maintained mileage in the country but that is the first time that I had seen it in tabular form.

The running joke among us here is that if you can drive on it without the need for 4 wheel drive and mud tires it's state maintained. Of course that is most certainly not accurate, but it feels like it sometimes.

Technically I don't actually live in New Bern, I actually live in River Bend which is its own little town just SW of New Bern. The main road in and out of River Bend (Shoreline Dr) is state maintained, but all of the side streets off of it are maintained by the HOA's of the various streets. It's pretty much the same deal in Fairfield Harbor, Stately Pines, Carolina Pines (etc.), with one main road in/out is maintained by the state and the HOA's take care of the side streets.

Any road that actually takes you somewhere is state maintained around here, though.

It's the same anywhere I've ever been in North Carolina. I'm not sure if there's a place where counties or municipalities maintain roadways.

The organization of NC's government is very oriented towards the state handling a lot of things that a lot of other states delegate to lower forms of government. NC also doesn't have home rule municipalities so they're big fans of having all the power concentrated in Raleigh.

[froggie]

Regarding Minnesota's mileage.

Per Article 14, Section 2 of the state Constitution, the Minnesota state highway system is limited to 12,200 miles, although the Legislature is allowed to exceed that limitation as necessary or expedient to take advantage of any federal aid made available by the United States to the state of Minnesota.  I believe it is for this reason that the Interstate highways were added under a separate statute (Section 161.12), and this Interstate mileage does not count against the 12,200 mile limitation.

Although I can't find anything now (it's possible that the Legislature lifted it), the County State Aid Highway mileage limitation was originally 30,000 miles.  Per Subdivisions 11 and 12 of Section 162.02 of the state statutes, turned back trunk highways and former municipal state-aid streets (from cities that were above 5,000 population but dropped below 5,000 population) do not count against this mileage.  Per MnDOT State Aid's 2015 apportionment book, the CSAH system has approximately 30,705 miles.

Cities above 5,000 population (as defined by the US Census, with a few exceptions) may designate a portion of their city streets as part of the Municipal State Aid Street system, as defined in Section 162.09.  They may designate up to 20% of their street mileage as part of the MSAS.  Former state and county state aid highways that were turned back to the city do not count against this mileage limitation.