Talking Michigan Transportation
The Talking Michigan Transportation podcast features conversations with transportation experts inside and outside MDOT and will touch on anything and everything related to mobility, including rail, transit and the development of connected and automated vehicles.
Talking Michigan Transportation
Take 2: Regulating traffic flow with stop lights at entrance ramps
On this week’s Talking Michigan Transportation podcast, some context from elsewhere on freeway ramp metering, where it works well and why.
First, Angie Drumm, deputy director of traffic and safety for the Colorado Department of Transportation (CDOT) region that includes Metro Denver, joins the conversation to talk about the history there and what’s been learned.
Later, Lawrence Dwyer, director of safety and mobility at the American Association of State Highway and Transportation Officials (AASHTO), offers a national perspective on the concept and other innovations in traffic safety.
This podcast is the second of two focusing on ramp metering. Last week, the conversation focused on implementation of the approach on I-96 in Michigan’s western Oakland County.
Hello, welcome to the Talking Michigan Transportation Podcast. I'm Jeff Cranston. This week I'm picking up on a theme I began last week focusing on the Michigan Department of Transportation's use of ramp metering as a means of regulating the traffic that gets on to I-96 in the new flex lanes in western Oakland County. This is a measure that's used all over the country to make for safer merging at busy interchanges. And after last week, after talking to Sarah Gill in traffic safety in MDOT's metro region, which includes greater Detroit, I wanted to follow up with someone in another city where these have been used for quite a while with success. So I spoke with Angie Drum, who's the deputy director of traffic and safety for the Colorado Department of Transportation region that includes Metro Denver. They've been doing it in Denver, a fast-growing metropolitan area, for some time, so she explained how things have been working there. And I also spoke with Larry Dwyer, who's the director of safety and mobility for the American Association of State Highway Transportation Officials, or AASHTO, and he talked about this from a larger standpoint and put it in the context of other innovative things going on around the country to make for safer traffic flow on the freeways. So I hope you enjoy the conversation.
Speaker 2:Angie, thank you for coming on the podcast. I wanted to get the perspective from someone who's been doing ramp metering for a while and Colorado has had success with this in the Denver metropolitan area, and I know from our discussion what I've read. You face the same challenges with funding and logistics that Michigan faces and many other states do when it comes to transportation. And first of all, I should tell our guests that you are a Spartan and originally from Metro Detroit, so you're part of the brain drain. We wish that we had that talent back in Michigan, but I love Colorado, so I'm sure you do too yes, beautiful place.
Speaker 3:Both I would say both are beautiful places that's right.
Speaker 2:That's right. So talk a little bit about it from your perspective. What kind of questions you have to answer and, I guess, what you've learned along the way about ramp metering and you know ways to make it better.
Speaker 3:Yeah. So I would say the some of the questions we often get from the public is you know, why is it's the simple, like, why, why, what, what? Why are we? Why do we have to stop at this light and then and then enter the? You know the system and you know, in short, it's really, it really is there to help, right, just like it's on, so that, like traffic you know, traffic that's on the main line isn't constantly stopping with this big platoon of cars that are, you know, coming on and trying to jam in and so to help sort of meter that pace of which cars are coming on and entering the system for a more effective and more efficient flow overall of the highway system.
Speaker 2:Do you have it anywhere else in the state outside of the Denver metropolitan area?
Speaker 3:So you know, we've had it in Denver metro area since the 1980s and just I would say, in the last probably five to 10 years it is starting to expand outside of what we consider our Denver metro area, further north and further south, as our population sort of grows along, you know, and extends into Fort Collins area and Colorado Springs area, which is to the south, and we also have it on our what we refer to as our I-70 mountain corridor, which heads into the south, and we also have it on our what we refer to as our I-70 mountain corridor, which heads into the mountains. And certain and those are those meters are only on, you know, when needed, which is primarily during, you know, winter or high travel season. You know whether people are going in the mountains for the, you know skiing, or to recreate mountains, for the, you know skiing or to recreate.
Speaker 2:And so we only have those on during really limited times and hoping not to get stranded before the tunnel by a snowstorm Not that that's ever happened to me.
Speaker 3:Yes, I feel like it has happened to many.
Speaker 2:Well, so I guess what do you think you've learned over the years about it? I mean, it's interesting to me. You've had it this long, you're still getting questions. But then again you've got so many new people moving to the area all the time and they're probably coming from an area where they've never used it and never had to drive with it. So change is hard, right.
Speaker 3:Yes, yeah, and you know that's a great question, because I think one of the things that we've learned is that we do need to have sort of the keep up the public, you know information, you know on what ramp metering is, what it does, the benefits of it. You know. Also, sometimes, you know, with maintenance, our system now, like where your system is bright, new and shiny, our system is not quite so bright, new and shiny, and so we have a lot of you know, maintenance concerns at this point and where we are investing quite a bit of dollars into helping, you know, upgrade our equipment and whatnot. But when a ramp meter is down for too long, right, people think it used to just going back to how it was, and then when it starts working, it's like a little bit of an adjustment. So, yeah, so I would say, you know, we just need to remind the public the benefits from time to time.
Speaker 2:I think I'm interested in how enforcement goes. Just like MDOT in Michigan does not have enforcement powers, we work with various law enforcement agencies, especially the Michigan State Police. You have the same relationship with your police agencies and the Colorado State Police, with your police agencies and the Colorado State Police. I saw one news story where they were looking at it and maybe it was that I-25 pilot you were talking about and the TV station found like 19 people running the red light in a matter of like six minutes and they talked to a trooper about it and what they can do in terms of enforcement. Do you feel like that's still a problem?
Speaker 3:they can do in terms of enforcement. Do you feel like that's still a problem? Yeah, I think I do think we have an enforcement problem, especially when you think about, like all, all of that, our police officers have to deal with.
Speaker 3:Enforcing or sort of ramp metering is not the top of the list, right? You know there's so many other things. So that's where we really need to rely on sort of the robust public information campaign so that people understand like, hey, I think most people abide, right, so you have a small percentage of that won't abide, and it's just not ramp metering, it's probably speed.
Speaker 2:You know, it's probably a whole litany of other things. Absolutely yes. If you're likely to disobey one thing, then you probably disobey others.
Speaker 3:Yes, yes, exactly, and so I do think it's that educational campaign that like as a reminder of like hey, this, you are running a red light, like you are at risk of getting pulled over, like that's to try to draw that parallel and you know, and could cause potentially an incident as you're trying to merge onto the highway, so yeah, so I think we really rely on that.
Speaker 2:Yeah, so when these stations were doing news coverage just a couple of years ago, and I guess again because they thought it was new. When you add it to a new corridor, and maybe again it's because you know new people are moving to the area. But I mean, are your, you know, are your feeds, your various social media feeds, populated with questions and complaints about this, or does it kind of ebb and flow?
Speaker 3:I think it ebbs and flows to ebb and flow.
Speaker 3:I think it ebbs and flows. You know, I think what you're referring to in the recent more I would say relatively recent media, it was because we were running a pilot program for a more sophisticated ramp metering system than what the public was generally used to. And so, right, you know, most of our system just comes on like time of day, right, and it reacts to the volume. Um, and what we were piloting was what we refer to as a coordinated ramp metering, coordinated adaptive ramp metering system, and so not only is it reacting to what's happening on the main line, but it's it's reacting to what the other ramps, like it's talking to ramps that are further upstream and and downstream, and then adjust like they're all talking, and then they all adjust based on what's happening. Um, so, like I said, very sophisticated, um, yes, very dynamic and also, um, we wanted to do the campaign because people could experience longer wait times at the ramp than what they're used to, and we didn't want, you know, we wanted people to understand the why in what we were doing.
Speaker 2:And there's been some discussion questions about why you can't alternate. If you have two lanes on a ramp, you can't alternate them in kind of a zipper merge style. And I don't know, does Colorado have you guys use zipper merge in work zones?
Speaker 3:We do. We do use that. Actually, that's a good point we get that's probably one of our top questions that we get about our ramp metering is like why are we setting up what you know the public refers to as sort of this drag race feeling between the cars? We both let them go at the same time and, generally speaking, we haven't found it to be a safety issue like a huge safety concern. We don't necessarily feel like we need to adjust it at this time. Of course, it's something that we're going to continue to look at and adjust if needed.
Speaker 2:Yeah, absolutely so. I guess you know what's your elevator pitch to somebody who's never really heard about this. I mean, you know maybe a friend or a family member that you talk to and they say so, you know what is it you do for a living. And if you talked about this, what would you say?
Speaker 3:Yeah, well, that's, I will actually talk to my family that live in Michigan still and give them, give them, help you with my elevator pitch, like that. You know it helps regulate and minimize traffic congestion with the cars coming on from the freeway Right. So that's like the number one benefit is that sort of evens out that platoon of cars that are like coming onto the freeway and trying to get in. Also, you know it improves safety ultimately. You know it improves safety ultimately. You know oftentimes we'll have, you know we'll have incidents, as you know, a ton of cars are trying to merge in and there's confusion and lane weaving, and so it ultimately improves safety as well. And of course there's, you know, we could argue there's environmental benefits because we're reducing sort of the stop and go nature of as cars are all coming on. So that, in a nutshell, I think those three things would be my key points.
Speaker 2:Yeah, no, I think safety is, you know, the imperative. But you're right about the environmental benefits too, just like a roundabout right, anything that keeps the traffic moving, and you know congestion means idling and that's you know that's emissions. So will your family be driving through 96 in western Oakland County, where MDOT rolled out ramp metering for the first time in decades?
Speaker 3:They will. They probably not every day, but on occasion, so I will definitely have a conversation with them though.
Speaker 2:They'll say it's all your fault.
Speaker 3:Yeah, exactly.
Speaker 2:Well, it's all your fault, yeah exactly. Well, it's also going to be. Are you familiar? You know that's? That's actually a flex route where they're able to use the shoulder as a lane. And there's an extension of the initial flex route in Michigan, which was on US 23 between Ann Arbor and Brighton, and that's going to have ramp metering at some point too.
Speaker 3:Oh great.
Speaker 2:I think so. I think there's going to be a learning curve and I know we're getting it already on our social media feeds. Again, change is hard but overall, people will learn it and, I think, appreciate why it's a good thing and understand that it's not like you said, it's not always on it's. It's a very dynamic system.
Speaker 3:Right.
Speaker 2:Yeah, well, thanks, angie. Thank you for talking about this. I'm going to be speaking with the mobility czar at AASHTO about this a little bit too, to get a national perspective, so you'll be interested to hear what he has to say. Okay, great, please stay tuned. We'll be back with more Talking Michigan Transportation right after this.
Speaker 3:Know before you go. Head on over to MyDrive to check out the latest on road construction and possible delays along your route. For a detailed map, head over to michigangov slash drive.
Speaker 2:Thank you again to Angie Drum of the Colorado Department of Transportation for her insight into how things are working there in metropolitan Denver. And next, as promised, I'll be speaking with Larry Dwyer, who's the Director of Safety and Mobility at AASHTO, and he'll offer a national perspective even an international perspective on the concept and how it works, making a repeat appearance on the podcast. Thank you, larry, for taking time to be here. Thank you, jeff, great to be here with you all. I really wanted to hear your take from a kind of a national perspective, maybe even an international perspective, national perspective, maybe even an international perspective on the ramp metering concept. As you know, the initiative in Michigan is just a couple of days old and it's actually been brought back after being tried several years ago for quite a while and then abandoned. But a lot of times, as you know, these concepts get resurrected under new circumstances, and that's the case here. But just, I guess, high level. Give me your take as somebody who studies traffic safety and operations on a much broader scale. What's your take on ramp metering?
Speaker 1:Thanks, jeff. My take on ramp metering is it's a traffic management strategy. It's been around for quite a while and it's basically just using traffic signals on freeway on-ramps to regulate the rate at which vehicles enter the highway and by controlling that influx of vehicles ramp meters help improve traffic flow, reduce congestion and enhance safety. Ramp metering has been around in the US since the early 60s. The first experimental ramp meter was installed on the Eisenhower Expressway in Chicago in 1963 and then expanded to the Kennedy and all the other expressways in Chicago Expressways in Chicago. Since then DOTs and cities have been kind of expanding ramp metering and tying it into other technological advancements such as data analytics and broader applications and urban freeway systems, and tying it into fiber systems and traffic management systems and really it's one tool in the toolbox that's been around a long time to help manage transportation operations in a corridor.
Speaker 2:What would you I guess high level broadly say are the circumstances where it makes the most sense.
Speaker 1:Well, ramp metering produces several proven benefits. One it reduces freeway congestion by spacing out the vehicle entry to the highway. It improves bottlenecks and freeway speeds by improving the traffic flow, rear-end collisions and merging collisions and you also have less stop-and-go traffic which can lead to these collisions and more kind of steady, free-flowing traffic. It also improves travel time reliability and increases the overall freeway capacity.
Speaker 2:I spoke earlier to Angie Drum, who's a traffic and safety expert, traffic and safety official in the Denver region for Colorado Department of Transportation, and she talked about how well it's worked there on the really busy freeways. As you know, denver is a very rapidly growing metro area. It sounds counterintuitive to use a traffic light to try to at least minimize stop-and-go traffic, right. So can you talk that through?
Speaker 1:Sure, I mean, it's one of the oldest tools in 60s. It's proven to work. Some of the benefits of ramp metering that the research shows are crash reductions anywhere from 15 to 50 percent, depending on the corridor you use it. Travel times can be reduced up to 48 percent and freeways speeds increased up to 62 percent, and then it has the added bonus of also reducing fuel use, and emissions are also reduced. So there's a lot of positive benefits to it. There's over 20 states in the US using ramp metering today, including California, minnesota, michigan, texas, washington, georgia, certainly Illinois, and then you also see it more often, I think, frankly, in major metropolitan areas with high traffic volumes thinking like Los Angeles, seattle, atlanta, chicago. We have some in the DC area as well. So it's a proven measure to help improve traffic flow, reduce congestion and enhance safety. I think that's why you see so many states and major metro areas using it today.
Speaker 2:So talk a little bit about what you've learned on its use in international cities.
Speaker 1:Sure.
Speaker 1:Ramp metering is not really unique just to the US.
Speaker 1:Countries like Australia, germany, sweden, the UK and Canada also use ramp metering as part of their intelligent transportation systems. For example, melbourne and Sydney have comprehensive ramp metering systems that are integrated with their dynamic speed limits and real-time traffic monitoring, and that achieves for them some measurable improvements in three-way performance to the next level. And by tying it into their real-time traffic management systems and monitoring in their traffic management centers, variable speed limits, kind of taking it to the next level, and also tying it into their traveler information systems and their message boards, which lets people know how long the travel time is going to be from point A to point B. Often a common measure will be how long to the downtown business area perhaps, how long to the airport, how long from one side of a corridor to the other, and that provides a lot of benefit to the travelers. They know about how long it's going to take and whether it's a normal commute day or if they're looking at some sorts of delays, whether it's weather, construction or some sort of crash or incident.
Speaker 2:Yeah, I think, as you and I have discussed before, the DMS board that tells me that what I think should be 20 minutes to get downtown and tells me it is 20 minutes is very useful. I find that to be a relief. And something I want to know is coming as the technology evolves and comes online, to find ways you know, either through CarPlay and Apple Maps or Google Maps or Waze, to put that information you know right into your vehicle. How many years from now do you think we won't need DMS anymore?
Speaker 1:I don't know.
Speaker 1:That's an interesting question.
Speaker 1:What we're seeing lately and sort of in real time is, for a long time, states, metro areas, collected information and sort of disseminated it on their own through news channels, radio channels, message boards, to let kind of people know what's happening.
Speaker 1:To let kind of people know what's happening. And right now, as we speak, traffic management centers are interacting in real time in many of our metro areas with third-party apps such as Waze, Google Maps, Apple Maps and others, and there's a two-way sharing and flow of information where people who are driving and using Waze, for example and I think Google Maps and Apple also have this feature now where people can note an incident, a crash, a stalled car, a pothole and let other drivers and travelers know in real time what's happening and that can be shared through the Traffic Management Center. And it's a two-way sort of communication that we didn't even have maybe five, ten years ago and it's just speeding up the flow of information and allowing drivers traveling public to make decisions about what routes they'll use, about when they'll leave, about what incidents are happening on the highway. It's really an amazing change that's just happened in the past few years.
Speaker 2:Anything else going on that you're excited about in terms of innovations or new things that are being piloted or implemented, you know, anywhere in the country or, I guess, anywhere in the world in terms of traffic safety and management of traffic.
Speaker 1:I think some of the things that we're excited about seeing is a lot of the driver assistance technology that's making a difference in real time in people's cars right now. Think of things like backup cameras, rear traffic sensors, forward collision warnings and sensors and automatic braking pedestrian detection. On some of the newer cars with automated braking, that's the vehicle itself providing drivers with assistance to avoid a crash, and I know from using some of these systems personally, it really does help people. It helps make them more aware and attuned to the environment uh, around them, and it's hard to measure how many crashes we didn't have and how many, uh, we saved, but, uh, I know people find that those systems valuable and useful and once people, I think, are accustomed to those and some of the newer cars, I don't think people want to go back to a time when they didn't have that kind of assistance.
Speaker 2:Yeah, I think you're absolutely right. I can't remember if you and I spoke about this previously, but I think that if you ask a lot of people how they feel about automated vehicles, they'll say you know, I'm not ready for that. Automated vehicles they'll say you know I'm not ready for that because, as anybody who's ever listened to the podcast knows, I think everybody says they're a good driver, but the other guy isn't. But the computer is free of emotion and all the other things that we do as humans, and I'm much more likely to trust the computer. And so, as these things phase in incrementally, I think you're right People like them and they say they wouldn't want to give them up. But if you ask them about automated vehicles, they'll still say no, no, no, I'm not ready for that. So it's going to take some time for sure.
Speaker 1:I agree, and I think the driver assistance technology is sort of an incremental step to more automated vehicles. Step to more automated vehicles where I think people are concerned and you see surveys that there's a very low acceptance rate of true automated vehicles at the moment within the general public something like 20 or 30 percent because people are afraid of giving up that control to a computer. But they're very much more comfortable with some driver assistance technology that will help them in doing what they need to do, whether it's blindside monitoring or rear traffic alert, for when they're backing up and there might be pedestrians, bicyclists, other cars behind them that they might not have saw or that are coming up quickly. I think people are comfortable with that sort of technology where the driver is still in control.
Speaker 2:Yeah, absolutely. And I think, going to your point about how quickly we come to not only accept it but take it for granted, I get really annoyed when I put my bike carrier on my car and then I can't use my backing camera anymore. Right, exactly, thank you, larry. This was helpful. I always appreciate your insight and especially your interest and focus on safety and how to make the roads safer for everybody. Still way too many crashes and too many people dying on our highways, so you really can't talk about it too much, I guess.
Speaker 1:Right, exactly. Thank you, jim. Always a pleasure to talk with you.
Speaker 2:I'd like to thank you once more for tuning in to Talking Michigan Transportation with you. I'd like to thank you once more for tuning in to Talking Michigan Transportation. You can find show notes and more on Apple Podcasts or Buzzsprout. I also want to acknowledge the talented people who help make this a reality each week, starting with Randy Deppler, who skillfully edits the audio, Jesse Ball, who proofs the content, Courtney Bates, who hosts the podcast on various platforms, and Jackie Salinas, who transcribes the audio to make it accessible to all.