Correct way to find interstate address

Most of the time, State highways are known as SR (for state road) and County highways are known as CR, so your example would be found as SR 121 (probably). You can prove this by positioning yourself ON the road in question and see what is displayed for your current location.

AFAIK, addresses do not exist for a real Interstate Highway. Any structure would have an address on an access road or frontage road.

Interstates are by definition limited access roads and in general should not have addresses associated with them.

Non-interstate highways are a different issue. I'm fighting with a POI geocoding issue of over 500 locations at the moment, and having a lot of trouble geocoding about 20% of them, and the majority of those problems seen to be because either incomplete highway addresses are given (the address just says something like "Highway 40", Hicksville), or are even gives an address number with a highway that I can't manage to look up. I think the main problem is that many times a "Highway" will have a local name that the location is really stored under. Fro example, in Raleigh NC, US 1 is called "Capital Blvd." even though the term US 1 is often used as if it were interchangeable by locals. And parts of Capital Blvd. / US 1 are also called Highway 401. But I expect that to look up things along this stretch of road you would need the local "Capital Blvd." name, and not the US route or the Highway numbers.

Highways do present problems with addressing. It is often difficult to know how they are named when loaded into the GPS. Standard abbreviations usually work, but there are times when they may be known by a local name also and that is how they are loaded.

Texas, with its access roads does issue street addresses with the Interstate number, but I-35 may be the correct designation from a paper map, but locally it's IH35 and that's the way the address is given but not coded.

The best thing that I have found is to browse the map in the area near where you think the address is located. Hover the pointer over the road or place a point on the road and see how it's coded in the map. Then try searching for that.

Address ?? We don't need no stinkin' address. We all know where everything and everybody IS !!

Try just entering "121" (for example) as the street name and the unit should present a list of streets that have "121" as part of the name. Then you can select whichever one is appropriate.

I find that often addresses are entered in USPS format, and try to follow that. Eg, "123 E 2nd St" is the USPS format for 123 E. Second Street. But I have repeated problems trying to guess the correct format for highway addresses. Sometimes, you just won't find them; the PO may use a different addresss (eg, Holmes Rd instead of HWY XX), or is very particular in how you format the input address. Here are some examples of formats that HAVE worked:

414 W US HIGHWAY 40
11373 US HIGHWAY 59

Other USPS-recommended formats:

INTERSTATE 35
INTERSTATE 35 FRONTAGE RD
HIGHWAY 101
COUNTY HIGHWAY 140
COUNTY ROAD 45
STATE HIGHWAY 45
STATE ROAD 78
STATE ROUTE 88
ROUTE 66

[See pg 69 of the USPS Addresss Standardization book, if you really want to dig into this.]

Recently, after having trouble locating a destination point by its intersection, I stumbled on the fact that I needed to hyphenate the cross highways (eg, I-35, US-169). I still need to look further into that; it could have been a one-time thing unique to that particular city.

This is a major pain in the xxx with Garmin. They don't seem to have a standard way of listing numbered highways. Some are listed as hwy, some as SR, US, etc. They even change the prefix along the same highway. Short of navigating to the area you want to find and checking how it's listed on the map, I know of no way to ensure that you enter the correct prefix.

I don't know if this is a problem with Garmin's software of with the map supplier.

Jack J

as you (DFW). I also have the same problem at times. Some places here give their addresses as a nuber on say I35, but my Garmin doesn't always recognize it.

Are these addresses located on a service road adjacent to the highway/interstate that you are trying to locate?

For those of you who have never been to Texas, most of the freeways there have parallel access roads on both sides. (In urban areas, the access roads are usually one-way.)

Many businesses are located on the access roads. The addresses for the business are "12345 IH-35, Austin, TX". They also may use the freeway name instead of highway number (e.g., Katy Freeway, Stemmons Freeway, etc.)

-Dave

I think it is the map data they get. What I have found is that some states are entered one way, and another state different. I think that different groups work on different regions of the country and came up with different standards. It is the same in google or yahoo too. Of course TX and a few other states are worse that normal....

What I have found is similar to above, use SR or CR. Sometimes you need the dash, and sometimes not. The best thing is to try and enter as little info as possible and see what happens.

Daniel