Old Highway Guide for California

[sdmichael]

I've been working on a guide for finding old highways on my website. So far, I've covered a general information and concrete roadways. I plan to cover road signs, bridges, and other roadway appurtenances. While most of the items are California-specific, some are good for any state or country. If anyone has anything to add or wants to help, let me know.

http://socalregion.com/finding-old-highways-a-guide-part-1/
http://socalregion.com/finding-old-highways-a-guide-part-2/

I also have no idea how many parts it will have. I hope to make it a decent guide for highway enthusiasts anywhere.

[J N Winkler]

Here are some clues to old alignments I have used in the past:

*  Non-uniform displacement of fence lines from roadway centerline (right of way acquired for the old road is sometimes not returned to the adjoining landowners).

*  Position of utility poles (utilities often won't relocate them unless forced to, e.g. when existing pole locations are covered by the new roadway alignment).

*  Long lengths of grass-covered embankment with a level crown, with or without culverts left in place.

*  When examining a length of road in a part of Google Maps that has property line coverage, an otherwise unexplained linear void running between parcels.

*  Lengths of loosely parallel pavement that have been converted into farm access roads, aggregate storage areas, etc.

These methods are largely specific to PLSS jurisdictions:

*  Lengths of mostly straight new alignment that run at a varying standoff from a section line that is usually never more than one mile:  this is usually a clue that the route has been lifted off an original alignment on top of a section line.

*  Curves where a north-south road crosses a survey parallel.  Because sections are notionally square in shape, while the surface of the Earth is curved, north-south section lines (except for meridians) are discontinuous across parallels.  Depending on how far a given north-south section line is displaced east or west of the ruling meridian, a reverse curve has to be provided to connect a road on top of a section line south of the parallel with the continuation of that road on top of the nearest section line north of the parallel.  The design parameters of the reverse curve are heavily dependent on the highway practice prevailing when the road was first durably paved.  Since the early norm (when open-road vehicle speeds were quite low--in the 35 to 45 MPH range) was to make the curves quite sharp, easing them or bypassing them is typically a primary design goal of any subsequent relocations, and oxbow lengths of old roadway grade are typically left on either side of a newer alignment.

This method is largely specific to mountain grades:

*  Typically, there is a first relocation reflecting a design attempt to "develop distance" by substituting long lengths of highly curved road on low grade for short lengths (curved or not) on high grade.  Again, this is a reflection of early design norms reflecting very low open-road speeds for both cars and trucks.  It is fundamentally a nonconservative approach, however, since the curves limit forward sight distance and therefore overtaking opportunity, while it is very rarely (if ever) economic to reduce grade all the way to 3% (the highest grade at which cars and trucks can maintain the same speed going uphill).  This is typically followed by a second relocation with the goal of straightening or bypassing curves to improve sight distance, even at the expense of a slight increase in grade, while providing a climbing lane for trucks so that they can easily be passed by cars; this approach protects operating characteristics going up the grade from fluctuations in the power-to-weight ratio of trucks as the truck fleet evolves in time.  As a result, any major mountain grade will typically have at least three alignments:  an original wagon track, a spaghetti alignment reflecting the first attempt at grade reduction through curve substitution, and a modern alignment (which may or may not still be in service) designed to provide good passing opportunity for cars while accommodating low truck power-to-weight ratios.

[Occidental Tourist]

I've been working on a guide for finding old highways on my website. So far, I've covered a general information and concrete roadways. I plan to cover road signs, bridges, and other roadway appurtenances. While most of the items are California-specific, some are good for any state or country. If anyone has anything to add or wants to help, let me know.

http://socalregion.com/finding-old-highways-a-guide-part-1/
http://socalregion.com/finding-old-highways-a-guide-part-2/

I also have no idea how many parts it will have. I hope to make it a decent guide for highway enthusiasts anywhere.

The new site looks really good.

[Atomica]

You know, YOUR avatar looks like something that could be used for "relinquished" routes through certain cities - that is a part of another thread, probably in another folder...

[sdmichael]

I've been working on a guide for finding old highways on my website. So far, I've covered a general information and concrete roadways. I plan to cover road signs, bridges, and other roadway appurtenances. While most of the items are California-specific, some are good for any state or country. If anyone has anything to add or wants to help, let me know.

http://socalregion.com/finding-old-highways-a-guide-part-1/
http://socalregion.com/finding-old-highways-a-guide-part-2/

I also have no idea how many parts it will have. I hope to make it a decent guide for highway enthusiasts anywhere.

The new site looks really good.

Thank you. I have been adding a lot more to the site lately, working to add County highways in addition to well... quite a few more pages. The site is never really done, hasn't been for the last 20 years. I hope to post the next part of the guide in the next few days.

[andy3175]

Great job Michael. As you know, you are among my teachers in learning about locating old roadway alignments and discovering highway history. You put together a very nice page that would have been great to have around back when I first discovered old alignments. Thanks!

[Alex4897]

*  When examining a length of road in a part of Google Maps that has property line coverage, an otherwise unexplained linear void running between parcels.

Not all cases will leave a linear void between parcels, some might just leave a boundary instead.  One local example I can think of is this:



A very long time ago it appears that Paper Mill Road continued on a straight trajectory and ended at Corner Ketch Road.  Since whatever extension took place, Pigeon Hollow Road was left as a driveway of sorts for the homes built along that short segment of road, and there is what appears to be remnants of a reaaaally old stone bridge just north of Paper Mill Road on the curve (in blue).  The property lines (in red) here however don't seem to leave space where the old alignment still exists, and they don't leave space where the old alignment used to be.  There is, however, a boundary that runs the length of the it, deviating no more than what appears to be a dozen feet or so on either side of the old alignment if these lines are accurate.

[Brian556]

Teach people to look at maps and think logically about whether a road could have been an old alignment. Does it leave, then rejoin the current hwy? Does it have 45-deg angle intersections with the current hwy? Be sure to mention that early highways had stair steps instead of diagonal sections.

Mention multiple realignments at cites. Bridgeport, AL is a good example.

Mention that everything that looks like an old alignment might not be, because the road was not yet on the state hwy system when that was the main road.

Mention that old alignments sometimes get chopped up, particularly in developing areas. OLD FM 2499 at Flower Mound, TX is a good example.

On roads that parallel railroads, the original highway sometimes jumped back and forth between different sides of the tracks, before being relocated so that it stays on one side. US 81 in Wise Co TX is a good example of this.

Mention that old highways were sometimes nowhere near their current alignment. In Denton Co, TX, SH 39>SH 24>US 380 was several miles further south that the current highway is today, between Denton and McKinney.

Mention that older state roads, in the early days, had narrower rights-of-ways, much like county roads have today.