Shreveport, Louisiana has the most dangerous onramp I've ever seen

[webny99]

It is a state law that traffic continuing on any frontage road must yield to all exiting and entering traffic.
[quote snipped]

Mind blown. To me that seems completely backwards, and I guarantee you everyone from much of the rest of the country would say the same thing.

And see, to me it makes perfect sense, for two reasons:

1.  Much better to require someone to yield who's going 40 mph on a local road than someone who's going 70 mph on a freeway.

2.  If traffic backs up, much better for the tailback to be on local roads than a freeway mainline.

That does make plenty of sense for an exit to a frontage road. That wouldn't seem as weird, at least to me, because both directions of the frontage road have to yield, and I know of many malls/plazas with very similar situations where the incoming traffic has right of way at a T-intersection...

... but thus far we've mostly been talking about and linking to examples of entrances, where it makes less sense.

[webny99]

Frontage roads are necessarily awkward when they are two-way. Sometimes the left turn has priority, sometimes it doesn't.

... but to someone from an area with very few frontage roads, basically no two way frontage roads, and certainly no two-way frontage roads where the left turns get priority (in other words, the entire Northeast and Midwest), that seems dangerous because it's so different and so counter-intuitive, even if it's perfectly safe in practice in places where it's the norm.

I think the Northeast is vastly different in so many ways compared to the rest of the country.  In most areas of the country, it seems like protected and/or permissive left arrows are very standard.  I almost feel like these people would get so irritated in the northeast where there are a ton of traffic lights without arrows.  Or, just how fast and crowded our highways really are in the northeast.  A 70 mph road in the south is only 5 mph faster than a 65 mph road in the north, but guaranteed the amount of traffic on that 65 mph roadway is considerably more than the 70 mph zones down south.  ...

Yeah, totally agree with that, and I think a lot of it (the lack of turn lanes and arrows, not the freeway speeds  ) has to do with the character of the area and the time period in which the road networks were developed. Suburbs in the South and West that have been built from scratch in the past 20-30 years are basically guaranteed to have wide boulevards, full turning lanes, and arrows at the signals, while that's pretty rare around here apart from a reconstruction project. Imagine how claustrophobic Rockland County, NY, or parts of northern NJ would feel to someone from the Phoenix or Houston area.

[webny99]

But there are millions of intersections all across the country where "who yields to whom" is not immediately clear. States vary in how they sign and mark intersections. This does not make them dangerous.

Millions? I honestly can't think of any (lest we drag up the "uncontrolled intersection" discussion we had a while back). But even so, as I said earlier, it doesn't make them actively dangerous as long as everyone using the intersection knows how it works and pays attention. But if this suddenly appeared tomorrow morning in this area, that would not be the case: likely several accidents would occur, followed by general outrage and confusion, before the drivers eventually adjust.

But let's not kid ourselves: Frontage roads are hardly a thing outside the South, so there aren't many locations where it would even be relevant. Ontario, Canada, has a few, such as along the QEW, but they usually go around the interchange independently instead of using slip ramps, as shown here.

Your implication seems to be that left turns having priority is dangerous, simply because that's not how the standard on-ramp works. That is ridiculously unfair.

Again, coming from an area where that's completely backwards and counter-intuitive, it does seem potentially dangerous. It just seems like another thing to keep track of when learning the ropes: always yield when turning left, except when...
But if drivers there know how it works from the outset and are used to it, then there's no inherent danger, unless of course two non-locals happen to meet at the wrong place at the wrong time.

[skluth]

But let's not kid ourselves: Frontage roads are hardly a thing outside the South, so there aren't many locations where it would even be relevant. Ontario, Canada, has a few, such as along the QEW, but they usually go around the interchange independently instead of using slip ramps, as shown here.

It's more accurate to say frontage roads are not commonly found in the Northeast than "hardly a thing outside the South." I've lived in Wisconsin, SE Virginia, St Louis, and now Southern California, and I've seen them in every place I've lived. Frontage roads, especially those found in what are often referred to as Texas-style freeways, are more common in the South. That doesn't make them hardly a thing elsewhere.

[sprjus4]

You thought all those examples were bad?

https://www.google.com/maps/@39.0166292,-76.4867258,3a,46.9y,94.53h,81.89t/data=!3m6!1e1!3m4!1snQg4-23w2yq4XX7F5VXSCw!2e0!7i13312!8i6656

[webny99]

But let's not kid ourselves: Frontage roads are hardly a thing outside the South, so there aren't many locations where it would even be relevant. Ontario, Canada, has a few, such as along the QEW, but they usually go around the interchange independently instead of using slip ramps, as shown here.

It's more accurate to say frontage roads are not commonly found in the Northeast than "hardly a thing outside the South." I've lived in Wisconsin, SE Virginia, St Louis, and now Southern California, and I've seen them in every place I've lived. Frontage roads, especially those found in what are often referred to as Texas-style freeways, are more common in the South. That doesn't make them hardly a thing elsewhere.

OK, so if we expand it to include the South and West, that would include all of those except Wisconsin, and I'm not sure that frontage roads are common there. The only one I could immediately find was along I-94 south of Milwaukee, and that's Ontario-style, where it goes around the interchange rather than using slip ramps.

[jakeroot]

I think two-way or one-way roads abutting freeways is actually quite common throughout the country, with fewer instances in some areas.

The one main difference between Texas, and elsewhere, is that two-way frontage roads usually aren't designed in a way that, from the air, appear to be one-way streets. I think this is the point that webny99 is making. Texas has very casual ramp design practices that I don't necessarily see elsewhere, where you can swing left across another direction, in a 'turn' that lasts sometimes 100 feet or more, where a sharp left and a sharp right might be a better design, and where the design would more clearly indicate priority. This on-ramp in Lake Stevens, WA is designed like this, although priority is still given to traffic entering WA-9. Traffic can pretty clearly see that the other direction has a stop sign, so that movement can keep going.

Now, still, in these cases, I've not seen one where the frontage road going in the 'wrong' direction (aka the direction without priority) did not have some sort of yield or stop sign posted (all posted examples here had some signage, and my example from Lake Stevens does as well). In these cases, I think drivers from elsewhere would be fine. If they were on the frontage road attempting to make a 'turn' onto the ramp, they may instinctively slow down to yield to traffic coming the other direction, but they'll quickly get the idea when that traffic stops for them. I don't see any danger arising from this situation. Off-ramps seem to be signed less, but on-ramps that cross opposing traffic seem to always be signed.

As an example of a non-Texas style interchange involving a two-way frontage road, Tacoma Mall Blvd runs along the west side of I-5 in Tacoma, WA. At interchanges, it swings out to allow standard ramps to and from the frontage road:

[jakeroot]

But there are millions of intersections all across the country where "who yields to whom" is not immediately clear. States vary in how they sign and mark intersections. This does not make them dangerous.

Millions? I honestly can't think of any (lest we drag up the "uncontrolled intersection" discussion we had a while back). But even so, as I said earlier, it doesn't make them actively dangerous as long as everyone using the intersection knows how it works and pays attention. But if this suddenly appeared tomorrow morning in this area, that would not be the case: likely several accidents would occur, followed by general outrage and confusion, before the drivers eventually adjust.

When I say "not immediately clear", I don't mean unsigned intersections (although I do use them very frequently). What I mean is that each intersection is slightly different from the next. The standard 90-degree four way intersection may be the most common shape, with a three-way T-intersection being second most common, but the point is that there are variations in angles, lanes, signage, priority, and whatnot all across this country. There may be standard protocols for certain designs or movements (left turns yield unless otherwise posted), but drivers don't approach intersections and assume priority simply based on the design alone: they look for signs, markings, signals, etc (none of these mean its an unsigned intersection, and priority is given to first arrivals). There are signs at these Texas on-ramps (not as many for off-ramps) to indicate who needs to do what. Left turns onto an on-ramp may have priority over oncoming traffic in law, but this ROW is almost always granted by signs in the field as well. Assuming there are signs, since this law does not exist elsewhere, I don't see why this design wouldn't work elsewhere.

That said, I'd rather the design weren't implemented elsewhere, as I consider it pretty weird and I hate the idea of traffic taking that long to cross oncoming traffic, even if they are stopped, but I don't think it would be a sea of collisions elsewhere.

[kphoger]

Actually, I see a huge difference.  In the first example, there's no merge lane.  ...

Geez, how did I miss that?  I triple-checked my examples before posting, too.   

I've not seen one where the frontage road going in the 'wrong' direction (aka the direction without priority) did not have some sort of yield or stop sign posted ...

Yeah, it's exceedingly rare.  I'm sure I've seen one or two cases in Texas, but I have little to no idea where at the moment.  In the case of typical Texas exits with two-way frontage roads, though, both directions of both frontage roads have to yield at both ends of the interchange.  This basic rural interchange, for example, has a total of ten yield signs.  It's pretty easy to imagine one missing or getting knocked down.

[jakeroot]

I've not seen one where the frontage road going in the 'wrong' direction (aka the direction without priority) did not have some sort of yield or stop sign posted ...

Yeah, it's exceedingly rare.  I'm sure I've seen one or two cases in Texas, but I have little to no idea where at the moment.  In the case of typical Texas exits with two-way frontage roads, though, both directions of both frontage roads have to yield at both ends of the interchange.  This basic rural interchange, for example, has a total of ten yield signs.  It's pretty easy to imagine one missing or getting knocked down.

With this in mind: are we going to say that a certain design, regardless of signage and markings, is more dangerous than another? I'm not saying there isn't logic to that (multi-lane roundabouts have plenty of signage and markings and still have issues), but I think it's an unfair assumption that doesn't give drivers enough credit.

[Scott5114]

Meanwhile, my first earliest memories of riding around in my parents' car revolved around the Tinker Diagonal (that stretch of I-40 where I posted that awful onramp upthread), so any time I am using a frontage road my instincts are to always yield to the ramps. When you see enough cars flying down one of those ramps onto the frontage road at 50 MPH, you tend to not want to take any chances.

[webny99]

... Left turns onto an on-ramp may have priority over oncoming traffic in law, but this ROW is almost always granted by signs in the field as well. Assuming there are signs, since this law does not exist elsewhere, I don't see why this design wouldn't work elsewhere.

That said, I'd rather the design weren't implemented elsewhere, as I consider it pretty weird and I hate the idea of traffic taking that long to cross oncoming traffic, even if they are stopped, but I don't think it would be a sea of collisions elsewhere.

Yeah, no disagreement from me on that. That's a system oddity that seems pretty unique to Texas and probably just became normal over the years. Most other states would either (1) make the frontage road one-way, or (2) build the ramps at right angles to the frontage road, or (3) separate the frontage road from the exit entirely, à la QEW.

I do get the concept of making the ramps free-flowing, but there are plenty of options that fit better with driver expectations and what we're accustomed to elsewhere in the road network. I know a lot of these are in rural areas, but certainly any that still exist in urban/suburban areas should be addressed.

[Finrod]

This thread reminds me of when I was 18 and in Los Angeles for the first time, going up what then was called the Pasadena Freeway, with the very short exit and entrance ramps-- I remember seeing an exit ramp with speed of 5 mph posted, because it looked like the ramp did a right-angle turn to a stop sign.

[Bickendan]

I was expecting ramps similar to the Arroyo Seco's... these (outside the US 50 one in MD) are straightforward. 

[skluth]

But let's not kid ourselves: Frontage roads are hardly a thing outside the South, so there aren't many locations where it would even be relevant. Ontario, Canada, has a few, such as along the QEW, but they usually go around the interchange independently instead of using slip ramps, as shown here.

It's more accurate to say frontage roads are not commonly found in the Northeast than "hardly a thing outside the South." I've lived in Wisconsin, SE Virginia, St Louis, and now Southern California, and I've seen them in every place I've lived. Frontage roads, especially those found in what are often referred to as Texas-style freeways, are more common in the South. That doesn't make them hardly a thing elsewhere.

OK, so if we expand it to include the South and West, that would include all of those except Wisconsin, and I'm not sure that frontage roads are common there. The only one I could immediately find was along I-94 south of Milwaukee, and that's Ontario-style, where it goes around the interchange rather than using slip ramps.

A few other examples
I-41 near Wrightstown
I-41 in Oshkosh
Madison Beltline
I-94 in Hudson

There are several others. I grew up in Green Bay, and frontage roads were part of the local vocabulary. You don't get to say these aren't frontage roads if you've changed the definition. You didn't state Texas-style frontage roads. A frontage road is nothing more than a parallel road giving access to property who would have lost access otherwise, not how interchanges operate within it.

[jeffandnicole]

A frontage road in Delaware has the yield to those coming off thr ramp. Centerville Rd at 141 North. Centerville Rd.
https://maps.app.goo.gl/VTeybXhG9cqqJhTZ9