GDOT to build truck only lanes on I-75 between Macon and Atlanta

[1995hoo]

Of course, we don't know what vehicle they actually used.

[noelbotevera]

Why not try zipper lanes to convert truck lanes into car lanes and vice versa, at times in the day...now that I think of it, it kinda feels stupid.

[D-Dey65]

It would be nice for this corridor, wouldn't it? 

There have been a lot of roads I'd love to see something like that on. If not that, then at least local vs. express lanes like the Capital Beltway in Alexandria. The dreaded Long Island Expressway seems like it might be a decent place for such an arrangement, even in suburban communities like Medford, where I grew up.

[Duke87]

Regarding places with an exclusive truck lane that prohibits cars, US-219 TRUCK outside Ridgway, PA, probably doesn't really count because it's a separate truck-only single-lane northbound-only road bypassing a steep downhill grade, though it's worthy of mention simply for the sake of completeness.

While it theoretically bans trucks, GSV somehow got a car on there.

Of course, we don't know what vehicle they actually used.

I suspect that GSV drivers often simply disregard phohibitions on auto traffic for the sake of not leaving gaps in image coverage. The 16th Street Mall in Denver is on street view, despite being off limits to all vehicles except buses. As is the Fulton Mall in Brooklyn, with similar prohibitions.

[andy3175]

I believe this project will certainly be one of the first, if not the first truck only lane project in the U.S.

Not the first.  There's a roughly 2-mile-long set of truck-only lanes on I-5 at the I-210/CA 14 megajunction north of Los Angeles that have existed for 30 years.  According to CalTrans, there is another set of truck-only lanes on southbound I-5 and southbound CA 99 at their merge south of Bakersfield...the goal being to keep the truck merge separate from the car merge.

It's funny thing: "truck-only" lanes in California may also have cars in them. Cars may use the "Truck-Only" Lanes at the I-5/I-210/CA 14 junction, as they can at the southern I-5/CA 99 junction. The objective of these "truck-only lanes" is to allow trucks to stay to the right as they pass through the busy interchanges and avoid having to cross significant merging traffic, forcing them to make multiple lane changes to stay toward the right of the freeway. I believe the OP was referring to a "truck only/car prohibited" configuration, which I don't think exists currently in California (and I'm not certain how cars could be excluded from the lanes). Yes, cars are discouraged from using the "truck-only" lanes based on signage, but car drivers would not be ticketed exclusively for the reason that they are driving in the "truck-only" lanes.

There is some info on California truck-only lanes here: http://www.dot.ca.gov/hq/traffops/trucks/ops-guide/truck-only-lanes.htm as follows:

Truck-Only Lanes

INTRODUCTION

What are truck-only lanes? Truck-only lanes are lanes designated for the use of trucks. The purpose of truck-only lanes is to separate trucks from other mixed-flow traffic to enhance safety and/or stabilize traffic flow.

Are truck-only lanes common in the U.S.? No, very few truck-only lanes exist. Most states restrict trucks to certain lanes, but also allow all vehicles to use the same lanes.

Does California have any truck-only lanes? Yes, California has two truck-only lanes and others under consideration:

Northbound and southbound I-5 in Los Angeles County at the State Route 14 split. Looking in the northerly direction, the truck lanes begin as two roads: NB at LA County postmile C043.925 and SB at C043.899. The NB and SB roads join at postmile C044.924 and continue together up to postmile C046.351. The total lengths are 2.426 miles (NB) and 2.452 miles (SB). The purpose of these truck lanes is to separate slower moving trucks from the faster general traffic on the grade. After constructing the new I-5 alignment, the original alignment was used for the truck-only lanes. This truck-only facility has been in place for about 30 years.
Southbound I-5 in Kern County at the State Route 99 junction near the Grapevine. This truck lane begins on Route 99 at Kern County postmile L000.629 (the equivalent of I-5 postmile R015.838) and ends on I-5 at postmile R015.492. The total length is 0.346 miles. The purpose of this design is to place truck merges further downstream of the automobile traffic merge of I-5 & 99.
Are trucks required to travel in truck-only lanes? Yes. Black and white signs direct trucks to use truck-only lanes. Black and white signs are enforceable.

Can passenger cars travel in truck-only lanes? Green guide signs encourage passenger cars to continue travelling in the main travel lanes and not use the truck-only lanes. However, since green guide signs are not enforceable, passenger cars are not prohibited from using truck-only lanes.

SOUTHERN CALIFORNIA FEASIBILITY STUDY

Has California ever studied truck-only lanes? Yes. In February 2001, the Southern California Association of Governments (SCAG) completed a feasibility study report (FSR) on exclusive lanes for commercial trucks. "Trucks" were defined as vehicles having three or more axles. The study focused on State Route 60, from I-710 to I-15, a distance of approximately 38 miles.

How was the route evaluated? SR 60 was evaluated for number of lanes, cross-sections, adjacent land use, over- and undercrossings and their clearances, and right-of-way.

What strategies were considered? Based on the above characteristics, three main strategies were considered: (1) allowing trucks to share the HOV lanes at limited time periods, (2) adding truck lanes to the freeway at grade, and (3) adding lanes above the freeway grade. The HOV lane option was dropped due to a number of barriers, including legal and funding obstacles.

What was the conclusion? The FSR recommended combining the two non-HOV strategies, with at-grade truck lanes built where feasible, and above-grade mixed-flow lanes built where right-of-way acquisition would be difficult. Above-grade lane sections should be kept to a minimum due to safety and operational considerations, as well as higher construction costs. Trucks would always operate at grade for safety.

By what criteria can truck lanes be selected? The FSR included a literature review which revealed that exclusive truck lanes were the most plausible for congested highways where three factors exist: (1) truck volumes exceed 30 percent of the vehicle mix, (2) peak hour volumes exceed 1,800 vehicles per lane-hour, and (3) off-peak volumes exceed 1,200 vehicles per lane-hour.

[The Ghostbuster]

Cars should not be using truck-only lanes. Only "trucks" should be allowed to use truck-only lanes. I know this isn't a perfect world, but the purpose of truck-only lanes should be to seperate truck traffic from automobile traffic.

[mrsman]

I believe this project will certainly be one of the first, if not the first truck only lane project in the U.S.

Not the first.  There's a roughly 2-mile-long set of truck-only lanes on I-5 at the I-210/CA 14 megajunction north of Los Angeles that have existed for 30 years.  According to CalTrans, there is another set of truck-only lanes on southbound I-5 and southbound CA 99 at their merge south of Bakersfield...the goal being to keep the truck merge separate from the car merge.

It's funny thing: "truck-only" lanes in California may also have cars in them. Cars may use the "Truck-Only" Lanes at the I-5/I-210/CA 14 junction, as they can at the southern I-5/CA 99 junction. The objective of these "truck-only lanes" is to allow trucks to stay to the right as they pass through the busy interchanges and avoid having to cross significant merging traffic, forcing them to make multiple lane changes to stay toward the right of the freeway. I believe the OP was referring to a "truck only/car prohibited" configuration, which I don't think exists currently in California (and I'm not certain how cars could be excluded from the lanes). Yes, cars are discouraged from using the "truck-only" lanes based on signage, but car drivers would not be ticketed exclusively for the reason that they are driving in the "truck-only" lanes.

There is some info on California truck-only lanes here: http://www.dot.ca.gov/hq/traffops/trucks/ops-guide/truck-only-lanes.htm [snip]

I am surprised that this website did not mention the 5/405 truck only lanes, although one may consider the 5/405 to be within the same interchange as 5/14.

Some cars have a legitimate reason for using the truck lanes on I-5. For instance, if I want to get off at the very next exit after the merge from 99 or 14 or 405 or 210 (as the case may be), I can take the truck only lanes and that will put me on the far right lane of the freeway after the merge and make it easier to take the exit.  The truck lanes are really just collector/distributor lanes in that case.

It seems though that the example in GA discussed in this thread are true truck only lanes.  All trucks travel in them, no cars are allowed in them.  That is far different than the situation in CA and along the NJTP.

[lordsutch]

It seems though that the example in GA discussed in this thread are true truck only lanes.  All trucks travel in them, no cars are allowed in them.  That is far different than the situation in CA and along the NJTP.

Actually the Georgia example, thus far, is pure speculation. We know nothing except (a) they're going to be called "truck lanes" and (b) they'll run from GA 155 south to the I-475/75 split. The financing (including whether they will be free or tolled lanes), access restrictions, lane count, and number of access points are all unannounced (and likely even undecided) at this point.

[afguy]

GDOT's website dedicated to the new mobility projects provides a few more details...

This interstate highway serves as an important freight and motorist corridor that supports
critical coastal port truck traffic and travelers from southern Georgia and Florida. While
truck and passenger car traffic are generally compatible, as the percentage of truck traffic
continues to grow, the increase in truck volume can and will accentuate operational
differences, leading to less efficient traffic streams and increased delays. For example,
compared to cars, trucks cannot accelerate as quickly on long grades. The corridor has
an important evolving need to ensure mobility for all its users and especially to maintain
Georgia's competitiveness in the movement of goods. By using the Express Lane concept,
and providing a dedicated system of lanes separated from existing general purpose lanes,
mobility is enhanced for both traffic streams. Project would include:
- Addition of two designated, separated truck lanes in the northbound direction along
I-75 from McDonough to I-475 in Macon.
- The truck lanes would be barrier-separated from the general purpose lanes
along I-75.
- The truck lanes will not be tolled.
- The final northern limits will be determined once additional environmental and
traffic studies are conducted.

[dfwtbear]

Why just northbound?

[lordsutch]

Why just northbound?

North is the uphill direction, for the most part. I'm guessing trucks are probably more heavily loaded northbound (headed inland from Savannah) than southbound too.

[Georgia]

plus there will be more truck traffic heading towards Atlanta rather than Macon.

[codyg1985]

I am sure money is a driving factor on why only northbound lanes would be built. Maybe there would be enough space left from building the northbound truck lanes to eventually build the lanes going south when the money is available.

[jeffandnicole]

plus there will be more truck traffic heading towards Atlanta rather than Macon.

Where do the trucks go after Atlanta?  They don't just disappear!

[froggie]

Regarding cody's comment:  if the uphill grade is the primary issue for truck-caused congestion, there would be no need for a southbound set of lanes.

[Georgia]

plus there will be more truck traffic heading towards Atlanta rather than Macon.

Where do the trucks go after Atlanta?  They don't just disappear!

well that wasn't the question put towards me, the question was why northbound on that stretch and not southbound; i gave my answer/guess and others have given theirs.

[Tom958]

Why just northbound?

North is the uphill direction, for the most part. I'm guessing trucks are probably more heavily loaded northbound (headed inland from Savannah) than southbound too.

McDonough is about 300 feet higher than Bolingbroke, at the northern end of I-475. So, if the road between those points were on a perfectly straight gradient, that gradient would be roughly 0.14%. As it is, the terrain is rolling, and a casual observer-- or, I suspect, even an experienced and cost-conscious truck driver-- would surely be unable to detect any general increase in elevation at all. I've traveled that way too many times to count, and I've never noticed any general grade-related slowing of truck traffic. That said, if there is to be only one such roadway, northbound would likely be the more sensible direction, mostly due to the likelihood that trucks are  more heavily loaded in that direction, as lordsutch suggested.

Maybe there would be enough space left from building the northbound truck lanes to eventually build the lanes going south when the money is available.

I'd agree. Right now a two lane reversible roadway is is being built from McDonough to I-675, and it fits under the replaced bridges with some relatively minor design exceptions. South of there, the bridges at GA 16, GA 36 and Rumble Road were similarly replaced. The ones at GA 18 and Juliette Road in Forsyth are probably tighter, and the remaining bridges are all original structures that'll surely have to be replaced.

Where do the trucks go after Atlanta?  They don't just disappear!

Hell, where do they go after McDonough? 


I think that this is one of the dumbest ideas I've ever heard, and I seriously doubt that it'll ever come to fruition. We'll see, I guess.