Transportation System Safety Goals & Considerations
The primary consideration of transportation system design is the safety of the people who use the roadways and intersections in each network. Traffic engineers strive to create efficient systems that reduce conflict points while also considering multimodal forms of transportation.
Listen as our transportation experts, Wade Greiman, PE, Rich Voelker, PE, and Mark Perington, PE, PTOE, discuss the critical components of a transportation network and the processes and steps they use to keep communities safe.
- Design Components of a Safe & Efficient Transportation Network (00:20)
- The Effects of Vehicle Speed on Traffic Safety (3:01)
- Addressing Multimodal Traffic Safety Conflicts (5:10)
- Funding Available for Traffic Safety Improvements (8:09)
- Traffic Engineering Resources at Snyder & Associates (13:29)
- Snyder & Associates Holistic Approach to Traffic Engineering (15:24)
Design Components of a Safe & Efficient Transportation Network
Wade Greiman (00:20)
Well, thanks for joining us today as we gather to talk about one of the most important things that we consider in the design process for our transportation system and its safety. We’ll just roll right into the questions here.
Describe different components of the transportation network and how safety plays into that decision-making process for design elements, such as intersections, roadway segments, multimodal considerations?
Rich Voelker (00:44)
When we’re looking at the transportation network for a client, we’re often looking at where the needs are either from a capacity standpoint or from a safety standpoint. Sometimes that safety is both a statistical issue of recording a lot of crashes along a corridor, or they have a perceived safety issue where they get a lot of calls of “this is dangerous.”
There’s a lot of attention being paid to older corridors. There are so many conflict points, so many ways to have crashes, and safety issues. Oftentimes there isn’t a multimodal element to those corridors. A lot of times, we’re looking at a potential reduction in capacity, of diminishing that from two through lanes in each direction to one and having a turn lane in the center. Maybe that additional width can be used for other uses, whether it be parking or bicycle combination.
Mark Perington (1:37)
Overall, one of the primary goals is trying to set a target of no roadway fatalities in our system. This is a great challenge because of everything we’re dealing with within a corridor, but it is something that if we take the safe system approach in which we look at all the elements. We look at the design, we look at the operation, and beyond that, we have driver behavior. All these things lead to how a corridor performs. That, in turn, plays into when we look at the networks. It’s the reality of different things that have developed over time.
A corridor can take on many lives over its years as it evolves from being a very busy highway that was perhaps first in place before our interstate system ever came to be, and it carried a lot more traffic. We have to look at how intersections behave from the standpoint of traffic control with stop signs, yield signs, traffic signals, and all of these relating to one another as vehicles travel down the road.
There are a lot of different modes we have to consider these days that are a greater priority than just getting a car from point A to point B. Many elements tie together, and at times it’s a challenge of looking at just one intersection, one driveway point that’s causing a lot of friction or conflict versus looking at the entire corridor and how it behaves and performs.
The Effects of Vehicle Speed on Traffic Safety
Wade Greiman (3:01)
As we look at the actual roadway corridor from a holistic standpoint and how each element within that corridor is supposed to function related to vehicle speeds and safety. Talk through how that speed and safety can complement each other or combat each other depending upon where you’re at with the roadway.
Mark Perington (3:20)
Our interstate system. A complete access controlled facility that has people traveling at a very high rate of speed to go long distances is one of the goals of why it was created for goods movement for people movement. Sometimes people associate that high speed as dangerous, yet our interstates are some of the safest facilities in our system. Why is that? It’s because of that access control and that predictability, and the expectations of drivers as they travel they shouldn’t have someone stopping immediately. They shouldn’t have a vehicle pulling out in front of them.
As we work our way through the various roadways in our systems, to arterial highways, or maybe down to just arterial streets and so on collectors neighborhood streets, you know, those speeds come down because the level of conflict starts to go up. We need people to have that lower speed as they have to deal with people pulling out of driveways, intersections in which there’s a lot of movements at one intersection, a lot of conflicts, we mix in other vehicles, buses, pedestrians, bicyclists, it just creates even further conflict. Any given intersection can have almost 32 different conflict points.
One of our goals as designers and traffic operations professionals is that we want to do all we can to help mitigate those things. I would add that for over 30 years now, we’ve been on-call traffic engineering professionals for the Iowa Department of Transportation for many operational and safety needs. We were helping some of the initial road diets, the four-lane to three-lane conversions in Iowa in smaller towns many years ago. We make things predictable so that we take away as much of that conflict as possible.
Addressing Multimodal Traffic Safety Conflicts
Wade Greiman (5:10)
When you start to introduce some of the multimodal facets of the corridor, like pedestrians and bicycles, the intersections are really where that all blends together. That’s when we start to introduce concepts like roundabouts or other types of intersection designs to help convey all modes safely and efficiently. What are some examples from a transportation safety perspective that your clients face that are challenging them on projects?
Rich Voelker (5:40)
A lot of the issues the clients I’m working with are facing are those intermodal conflicts of cars and pedestrians. As Mark alluded to the unexpected situation of suddenly, they’re not used to seeing a pedestrian there, and suddenly there’s a pedestrian there. Then dealing with those impacts, because those users are particularly vulnerable, pedestrians and bicyclists. A lot of those challenges come from the behavior of the vulnerable person. Think about how bikes behave and stop sign compliance and things like that. Those are hard to predict hard to control, and they are a constant challenge for our clients in trying to diminish the hazards that people see. There are a lot of near misses and other issues related to intermodal conflicts.
Mark Perington (6:27)
I think some other challenges we see are where we have an older design. I mean, we have some roadways and facilities that were put together clear back in the’40s, the ’50s. What we see over time is that it may have been an appropriate design for the level of traffic and what was going on in the area, but things changed. Again, sometimes we may have densities go down, and volumes drop. But in many cases, the thing we notice is the challenge for agencies is that land use has changed adjacent to an existing facility and that facility may all of a sudden experience a lot more stopping and turning traffic in the middle of a corridor. Therefore, it’s how do you have to adapt and change to recognize that we’re going to have safety conflicts with all the new turning traffic and people stopping more often.
We may create other problems by introducing a traffic control device on a high-speed highway where some of the safety performance of a new element can be worse than maybe what we’re trying to correct or prevent. Maybe we can get rid of these dangerous right-angle crashes in which people are getting hurt badly. The trade-off maybe we have to accept there may be a higher degree of rear-end collisions because now people are stopping more due to a new traffic signal. Something of that nature. It’s a challenge in how we present that to the public, making sure they understand the reason we’re doing the type of solution we’re doing will have the best net outcome for improving safety at an intersection or in a corridor.
Funding Available for Traffic Safety Improvements
Wade Greiman (8:09)
A lot of times, cities or counties don’t necessarily have the financial resources to address all of their safety issues within their network on their own. Maybe talk through a little bit about the different funding sources that they could leverage from the state or the federals to bring toward a project that has safety issues.
Mark Perington (8:28)
Sure. I know in Iowa, as well as a lot of the Midwestern states, Wisconsin, Nebraska, Missouri. Many have some sort of a traffic safety funding element created to help with projects. Specific to Iowa, we typically look at a couple of different programs. The Traffic Safety Improvement Program (TSIP) is an excellent one that has been around for probably 30 years now. It’s a very quantitative process that looks at crashes looks at what an improvement measure maybe that will help with the benefit-cost ratio. To prove that this is the right approach to do and we can bring funding to the table. Maybe we can approach the idea of, “Hey, this intersection’s getting so busy that we need additional traffic control and what is the proper type?” Whether it be as simple as a four-way stop, or is it more elaborate such as a roundabout intersection or a traffic signalized intersection? That’s one element.
At the county level, there’s the Highway Safety Improvement Program (HSIP), which again it’s another level of funding we can bring to county rural roads to help with a lot more challenges, such as run off the road type crashes, hitting fixed objects, relevant to their jurisdictional concerns. There are sources there.
If there’s a much larger problem, usually there are federal funding streams through the departments of transportation, in which, again, they typically have a top 100, top 200 lists that they look out within their state. A lot of that is about looking at the frequency of crashes versus the severity of crashes. We certainly take a very big focus on the severity of crashes. Are people getting hurt at these intersections? Those are the places where we also try to help our agencies with taking a strong look at what can be done to mitigate the outcomes of these collisions.
Again, these funding sources, as Wade mentioned quite often, and I think some people, they know they’ve got crashes in their community, it’s taking a systematic approach. We’ve got ten plus years of data at our fingertips here in Iowa, at least that we can bring up and look at and say, where’s the severity? Where is it occurring the most? How do we zoom in on and say there are likely improvements? Most importantly, can we bring funding to match in with whatever the agency policymakers may have decided to do to result in a good project that will make the most impact on improving safety?
Rich Voelker (11:03)
It’s also important for our clients to realize that safety improvements don’t have to be expensive either. There are quite a number of safety improvements that can be on the radar, especially as there’s that zero fatality goal. To always have that in the back of their mind, as they’re doing Capital Improvement Plan type work. Where they’re perhaps overlaying a roadway, that’s an excellent time to take a look at the safety of the corridor. There are a lot of issues out there that can be solved with very inexpensive additions to a project to be able to vary greatly enhance the safety of a corridor. An example is an overlay project and taking a look at the corridor capacity and usage and looking at striping it a different way.
We talked earlier about four-lane to three-lane conversions that are called road diets. Those can be very inexpensive projects, it’s mostly painting, and when you’re coupling it with overlay or regular road maintenance, that might be a refresh on the payment surface. That’s a great time to take a look at that and potentially add a fairly significant safety benefit by removing the potential issues or conflict points and not affecting the capacity or usage of the roadway. Another one Mark that I’ll prompt you on is the availability of the Iowa DOT Traffic Engineering and Assistance Program (TEAP). It’s a generally free service that the DOT provides for smaller communities and various traffic safety issues.
Mark Perington (12:29)
Correct, for smaller agencies that might only have a city engineer who has to wear so many hats or perhaps some public work staff. They can request assistance through the Traffic Engineering Assistance Program (TEAP) to deal with an intersection project, a corridor project, to look at what is going on. We’ve got safety problems. How can we deal with that? It provides that assistance that they don’t normally have. Usually, the only level of contribution that the agency needs to make is A making a request and good justification for it and B perhaps assisting with some input on local conditions, data collection, background information. As Rich mentioned, really kind of a zero cost to them, other than a little bit of their staff time, and that can lead to results. Those traffic studies and reports are usually very effective for turning those into safety dollars that will help realize the ability to get the project done for the community.
Traffic Engineering Resources at Snyder & Associates
Wade Greiman (13:29)
Kinda walkthrough, why clients would want to call us to help them solve some of their safety issues within their corridor system?
Mark Perington (13:37)
I think one of the things that we do well and we’ve prided ourselves on over the years is the fact of taking this systematic approach and looking at everything. Quite often, we talk about the four E’s: engineering, education, enforcement, and then emergency response. Well, we can’t control emergency response as much, but we very much can get involved in these other elements of education and enforcement. The education being, how do you interact with the public and make them aware of what it is trying to do? And enforcement is also the way we try to coordinate with law enforcement. When we look at problems and issues, I’ve always taken an approach that when we’re dealing with these things, I can talk about a change in traffic control or a change in speed limit or things of that nature. But at the end of the day, it’s also law enforcement that’s going to have to deal with those things.
I think those are elements of what we bring into the other very primary E that we’re involved in the engineering, which is taking this very total approach to solving some sort of a safety problem, again, in a corridor at an intersection somehow in the transportation system. Very much try to look at all the elements that relate to it—many times when we’re doing traffic engineering. We’re kind of coming in after the fact and talking about, well, can we change the pavement markings and make an impact on how vehicles behave or drivers behave? Can we change the signing? Can we change the lighting? Are there other things we can do that perhaps is not a major infrastructure investment but subtle things that could have a big impact on crash mitigation in an area?
Snyder & Associates’ Holistic Approach to Traffic Engineering
Mark Perington (15:24)
I think the other thing we try to do too is look at all the different influences on the driver behavior. There are so many things beyond just, well my road is straight and flat, what’s the problem? It’s all these other influences of the land adjacent, the driveways coming in, the type of vehicles that may be merging in or out of traffic. How does it appear to the drivers trying to navigate this road? What are we dealing with, with drivers? Are we near a high school where every year we get new 14, 15-year-olds that are learning how to drive? Are we dealing with elderly drivers that have different characteristics, their reaction times, their vision, how they behave within traffic?
I think it’s just trying to always make sure we take this holistic approach to look at everything related to it when we try to come in and solve a problem. We also believe very much in the right sizing. It’s making sure that if we’re looking at a safety problem, well, what is the right solution related to that problem? At times we don’t need a sledgehammer just to put a push pin in the wall. It’s making sure we pick the right thing that will still get us the safety mitigation but perhaps isn’t an incredibly large investment by a public agency. We just try to make sure we come up with the best solution that fits what the problem is.
Rich Voelker (16:50)
One of the things that clients look to us for is that we have a presence. People are fairly aware that one of our largest practices is transportation. We have an extreme depth of staff. Quite honestly, this is the type of work that gets us to other locations where we might not have an office. A lot of that goes to the usefulness of that knowledge and that expertise and being able to translate that to any situation in any community. When you can come from the outside and take a look at a problem that people are concerned about, that’s where we can provide the most benefit.
Wade Greiman (17:31)
I think as far as the experience and the depth of our staff is concerned too, we also can do soup to nuts as it relates to transportation. We can start with transportation planning, developing a master plan for a community as it relates to capacity, future roadway network improvements, safety improvements, all the way through to final design and construction administration, and observation for those actual improvements so that they get done correctly. It’s the depth of staff, and it’s the comprehensive experience that we can bring to bear to any city, county, state jurisdiction. To make sure that their safety needs are met.
Wade Greiman (18:11)
On behalf of Mark and Rich and the rest of our transportation professionals here at Snyder and Associates. I’d like to thank you for joining us as we talked through some of the passions and expertise that we bring to you related to safety improvements within the transportation network. Thank you.