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Module 1: Multimodal Transportation Systems

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Multimodal Level of Service for Automobile Modes

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In this, uh, lecture, what we'll go ahead and do is continue our, uh, series and multimodal level of service and look at, uh, how do you develop it for the, uh, automobile mode. Now, remember, uh, we are developing multimodal level of service. Uh, but we are still looking at the modes individually. However, under the umbrella of multimodal level of service, uh, by the end of the next lecture, you will see that we would combine all of these, uh, um, level of service for different modes. Uh, we'll combine it for one segment and have, uh, for that segment, uh, there will be multiple levels of service each representing each of the modes. So first we are looking at, uh, individual modes. Uh, last class, we looked at, uh, public transportation from the point of view of public transportation. Today, we'll look at it from the point of view of, uh, automobile or your personal vehicle, personal car. Um, so like I said, we've already looked at public transportation. Uh, now when we are talking about, uh, an urban street, there are multiple modes that are operating on an urban street, right. That may be your automobile. There may be public transportation. There may be bicycle pedestrian. So. Uh, it, it is unfair to only develop a level of service for one particular mode on that street. Right. And historically, that's what we have been keeping on doing is that, uh, the entire street, uh, is represented by just one level of service. And that level of services skewed towards, uh, motorized vehicles. It is not geared towards the car per se, but it is skewed towards the motorized vehicles. So level of service of a street, when we say we usually used to mean that a level of service or a motorized vehicle, but now since we are moving away from that concept and we're moving into the concept of, uh, or the realm of multimodal. Um, transportation. So now we have to develop a level of service, keeping multiple modes in, uh, our view. So this is what we are doing now. We are considering all the travelers on a facility when they perform an Alison decision meeting. So not only looking at it from the point of view of one mode. So when we try to do that, we can, uh, develop, uh, the level of service, uh, in two different ways, right? We can either develop a level of service. When there is spatial segregation of modes for, uh, that is right away. And that right of way is divided for automobiles, pedestrians, bicycles, and transit, maybe, uh, a single piece of right of way has dedicated, um, uh, itself, four different modes, right? So that is spatial, spatially segregated. So you, and develop a level of service when there is a, this type of, uh, segregation between. Uh, between different modes, uh, the trade-offs was, is to, uh, would be to then how to locate, how much of space to give, or how much of, right of way to give to each of these modes. Right? Uh, depending upon the space you give, uh, it can carry, uh, it can have a different carrying capacity. It can have different accessibility. So all of that will then decide the level of service, which can then be decided by one of these parameters, which could be the. Right of way that is allocated. So that is how you can develop a level of service. Uh, for, uh, when there are multiple modes, but they're segregated, especially, or you can also develop the level of service when they are, uh, temporarily segregated, uh, temporarily segregated means, uh, at one point in time only few modes can, uh, uh, access that facility. Right. For example, if you have, if you are at a signalized intersection, uh, when you have green for, uh, green, for a motorized vehicles, you will have a red for. Uh, separate Austrians and non-motorized vehicles. So, uh, then, uh, that time that you're you're, you're, you're, uh, you're, you're segregating the modes based on time, right? Uh, during this time only these vehicles will move during the other time. Only those modes will move. So that is called temporal segregation of modes. So you can have a level of service, uh, based on temporal, uh, segregation as well. So if you combine these two and look at this picture, Then you can say that, uh, uh, along the links along, usually the links, uh, you can develop level of service based on spatial segregation when you will have, uh, different right-of-way allocations for, for different modes. Uh, whereas, uh, at, at nodes at certain nodes, what you can do is you can have. Uh, or et cetera, or certain intersections, you can, uh, have a level of service based on, um, uh, based on how, uh, at what time multiple modes can move. Whether at a green time, only one mode can move, uh, or multiple modes can move. And then based on how much time they get, uh, the level of service can be determined, right? So that is what you can either do one or the other. But there are several times we'll have, when what happens is there is interaction between all of these modes right now, a typical case would be an ant signalized intersection, right? Uh, you would, uh, at a signalized intersection, you'll have temporal segregation, but an unsafe at an unsynchronized intersection, you are bound to have. Uh, interaction between various modes because, um, based on personal judgment, a cycle may decide to turn left. Whereas the, there may be a true vehicle coming, uh, and then maybe an interaction between these two. So maybe the cycle has to stop or yield to that true vehicle. So there, based on those interactions, there may be a level of service that could be developed, right. And many of our streets also, when you see on the right of way, Uh, pedestrians, uh, due to lack of pedestrian facilities, they walk on the, on the right of way on the pavement. Then there is interaction between the way colors, vehicular movement and the pedestrian movement. So what happens, or you can develop a level of service for that type of situation as well. So there are multiple ways in which you can develop a multimodal level of service, uh, and that is the beauty of a actually multimodal level of service. Now you can ha you can cater for the interaction as well as the. A spatial temporal segregation between these modes. You can keep in mind those things and then developer level of service. So, uh, if you recall, we have already gone through, uh, uh, uh, this concept of dividing up a facility or a roadway segment, or a facility, uh, or a roadway segment into various, uh, small little chunks. Uh, when we have developed the level of service for bicycle or pedestrians, this is how we showed you. Uh, so if you quickly look at it and if you think that, uh, uh, the, the direction of travel is this way. And, uh, this entire, uh, this entire thing would be the facility, right? Uh, I'm in from here onwards. So this entire thing would be the facility, but as this facility is divided up into various segments, these would be the segments, right? The segment would include the. Intersection include the intersection, right? That would be the segment. Whereas if you don't include the intersection only, uh, this distance would be the link. So you can again remember. So what is an intersection and intersection is. Uh, uh, um, uh, intersection of two links. Uh, if you consider the link plus the intersection, that is the segment. And if you consider multiple segments, that is the facility. Now usually a multimodal level of service does, is it breaks up a facility into different segments, not into different links, but into different segments. So the segment. In done, uh, is broken up into a link and a intersection. So what happens is you, you develop a level of service for the link and the, uh, intersection aggregated up to the segment, then have levels of service of each of the segments. Which can then be aggregated up to the level of service at their facility. So that is the entire idea. And you do that for all of the modes right here. First, we are going to start showing you with the automobile mode and then it will be the same process would be followed for the bicycle and pedestrian modes and transit modes, but the variables would be different in each of the different cases. So that's what, uh, is the entire concept of developing a multimodal level of service. For one facility, essentially what happens is that facility would be linked, weighted averages of the segment scores. So each segment will get a level of service score, right? And then for the entire facility, you will weight it by length. So one length, one segment, like maybe longer one segment, like maybe shorter. So you a weighed by the segment length and aggregate it up, uh, for all of the segments into developing the level of service for the entire facility. Uh, you can also do, uh, uh, levels of analysis, different levels of analysis. Uh, for level of service, what you can do is you can either do an operational analysis of an existing roadway, right. An existing roadway, uh, which is open for traffic and has been, uh, operating for the last 10, 20, 50 years. So you can do an, uh, uh, MLS. You can develop an MMOs for the operating segment, or you can do it, uh, in the design stage as well. Uh, when you are actually designing a new road, Or you are designing a widening of, uh, existing roads, so you can see how the, uh, amendment lowers would change. When you add a lane, for example, or when you convert a signalized signalized intersection into a signalized intersection, what happens to the MMOs? So you can do that at the design stage as well. And, uh, obviously you can do it later at a very, a planning stage or a preliminary engineering stage. Uh, however, at that point you wouldn't have the data that, uh, uh, because it's still at the planning stage. So what you would do is you'd have to, uh, uh, get data from similar facilities elsewhere and then predict that this is what is likely to happen, uh, when you would design or operator facility off. Uh, this magnitude. So, uh, you can develop levels of service at different times, uh, off, uh, operations from planning to design, to actual operation stage as well. Uh, so, uh, this is how you can, uh, uh, con conceptually the MMOs. Uh, although it is, uh, looking at the levels of service of, uh, all the modes, but the automobile mode still stands out because. Because of the, um, uh, measures of the, uh, variables that are developed are that are used in developing the level of service. They still are, uh, measures that can be, uh, measured, uh, measured the cream you observed in the field. So using those kinds of parameters, this level of services developed, whereas, uh, the levels of service for pedestrian bicycle and transit are based on scores that are reported by travelers, indicating that perception of. Uh, service quality. So the levels or the levels of service of pedestrian bicycle and transit are still based on the perception of the users. Um, whereas the level of service of an automobile mode is based on actual, uh, feel measurable, um, parameters, uh, such as speed delay and so on and so forth, right? So this is how you can conceptually think of how they are different from each other. Although for one street, we are going to develop a multimodal level of service for each of these modes. So here is an example, uh, based on the highway capacity manual 2010, which was developed in the U S uh, you will see that, uh, streets, automobile level of service. Uh, all of them have these, a through F scales, which is common for all of the modes. Uh, but then, uh, what you would have is a different definitions for a. For, um, different modes, for example, an automobile level of service and a would be no delay at an intersection, uh, whereas for a transit, uh, level of service or quality of service, it would be more frequent stops, more frequent service stops and amenities. Right. So a difference, you can understand how level of service is calculated for a transit versus a automobile. Now it may be on the same street segment, right? The same street segment, uh, which has a signalized intersection and a bus stop. Uh, in the, in the sec in the segment. Now you can develop a level of service, uh, differently for, uh, different, uh, modes, similarly, a bicycle quality of service. It would correspond to complete system, uh, for all types of users. Right, uh, based, uh, it may be not only for, uh, experienced, uh, bicyclists, but also for, uh, kids, toddlers and leisure bicyclists. So bicycle facility that is good for everybody. So that is kind of a level of service aid. When you look at it from the point of view of bicyclists. And then finally, when you look at, look at it from the point of view of pedestrians, it would be something like a complete system, easier to access, uh, easier to cross, uh, improved comfort. So. You'll see that they are more perception oriented. These three are more perception oriented and pedestrian being the most perception oriented. Uh, whereas, uh, automobile is more, um, uh, based on, uh, um, uh, field measurable values, right based on field, which is like you can measure delay at an intersection. Uh, if you are, uh, if it is a signalized intersection, it is the delay. Uh, it is essentially the red time for which you are to wait if there is no queue. Uh, that, uh, but if it's an unsynchronized intersection, then maybe if you're at a minor street that your delay is different as opposed to if you're in a major street. So that is how, uh, these levels of service conceptually look like. Uh, it's easy to understand if you, if you show these pictures and we'll compare them side by side, then you know, what is an a versus what is an F uh, we just looked through the, uh, descriptions. You can similarly go to the F descriptions. Uh, now when we start looking at the automobile mode, Uh, you, uh, but we have already given you a, a brief, uh, understanding, uh, in the beginning of the, the class that the level of service of an automobile mode, uh, depends upon, uh, speed and especially what speed is it? It is the travel speed as a percentage of base, basically flow speed, right? If, uh, if you know the base free flow speed for that segment. And now if you measure. The actual travel speed on that segment. What percentage, uh, is that actual speed of the base free flow speed? And based on those percentages, if it is greater than 85%, and if the VBC ratio is less than one, then it's level of service. A and, uh, as the percentages, uh, decrease the level of service falls, uh, of course, if VVC ratio is greater than one, then the entire segment is a level of service. So that is usually how you calculate, how you measure a level of service for automobile modes. What you have to be careful is that, uh, given the direction of travel, uh, if it's, if it's, uh, a divided, uh, street segment, then you have to develop a level of service for each direction and not develop one level of service for the entire facility. Uh, however, if it's an undivided segment, then you can. Uh, uh, sometimes have only one level of service for the entire facility. Uh, basically flow speed, uh, from a recall it's the speed under uncongested conditions, right? When there is no condition, uh, the speed at which vehicles can go, that is the base free flow speed. Uh, so if you now look at, uh, our facility, and if you're considering to develop a level of service for automobile mode for that facility, That may be divided up into various segments, right? And now you have to develop the level of service for each of these segments in order to then have an aggregated value of level of service for the entire facility. So why is it important for, to have for habit, uh, for developing the level of service for each segment? That is because, uh, the segments may be of varying length. These are similar lengths, but then you see these animals. Different lengths, uh, than the, where there may be multiple access points within each. Uh, within each of these, uh, uh, segments, which may cause a F uh, further delay. So, uh, in addition to delay experience at signalized intersections, which is controlled delay, you may have a delay due to access roads, and that may lower the speed. And like we just saw if the speed lowers when compared to the base base free flow speed than the level of service of that segment false. So you have to. Break it up into different segments. And for each of the segments, you have to calculate the volume to capacity ratio and basically flow speed. And the travel speed. If you do that, then you will be able to develop, uh, the level of service for, uh, the automobile mode, uh, for a particular segment. Okay. Again, a few more things to remember when you're developing the level of service for automobiles. Is D uh, analysis, uh, period. Uh, usually what we do is, uh, we develop, uh, the level of service for the peak. Uh, 15 minute flow. Uh, so, uh, the peak hour, we look for the peak 15 minutes within the peak hour and develop the level of service for that. Uh, why that is because we want to design our streets or we want to be, have our streets operating at an optimal level of service during the worst condition. Right? Peak periods are usually the worst congested. Our times and the peak 15 minutes within the peak hour is D uh, uh, is even worse, uh, condition. So that is the time if we design our road to, uh, uh, not fail during that times, uh, then, uh, it will easily carry, uh, uh, the traffic during other, uh, non-peak hours or normal hours. Right. So that is usually our, uh, uh, our, uh, period of analysis. Uh, between 15 minutes to one hour, uh, for planning analysis, 15 minutes, uh, a 15 minute analysis period is used in the peak. Our factor, uh, is estimated, uh, so that we can then aggregate it. Uh, we can then develop hourly or, um, daily, uh, uh, ranges for, uh, level of service, uh, for operational analysis though, of 15 as, as PDF should be used, uh, for a 15 minute P-Card period should be used. Um, we've already gone through this. You have to develop the volume to get better. uh, the ratio is meant for the lean group serving the through movement right now. That is another important thing to realize. Uh, there may be multiple lanes in the road. Uh, so you have to group those lanes, uh, which are allowing through movement. Right. There may be one, there may be three lanes, but the outermost lane, uh, maybe only four left turn, right? So there may be only two lanes that are going through. So when you're developing a, a level of service, you have to group these lanes accordingly, and it is for that group, uh, as a composite, you will be developing the level of service. So that is something to keep in mind. If there is only one lane, then, uh, you just develop it as one lane. But, uh, when, whenever you have multiple lanes, Uh, that is what you have to remember, uh, travel, uh, basically flow speed. We've already looked at, uh, travel speed is the ratio of the segment length to the through movement travel time. So, uh, based on, uh, how much segment it is, you'll be, remember we are waiting it by the segment length. So we have to take those links into consideration. Uh, so if you just look at the simple, uh, flow of, uh, developing these level of service, uh, you determine the basically flow speed. You determine the travel speed. Uh, there is an intermediate optional step of determining the spatial stop rate. Uh, the special stop rate is nothing but. Uh, if the, if the true vehicle has to stop because of those access points in between, uh, within the segment, right? We showed you that diagram, uh, where there may be these access points here, and maybe the true vehicle has to stop because of these, uh, vehicles coming out of these access points. So, uh, there may be, if you determine the spatial stop, uh, rate, that means in space, uh, how many times. The vehicle had to stop because that stopping the vehicle, meaning the speed has to go down. So that gives you an indication. Uh, if you add that on, that will give you an indication of what level of service that street is providing for the motorized vehicle. But that is an optional step. If you do want to add it, uh, you can add it otherwise. Uh, these two are good enough to determine the automobile level of service. And this is what we meant when we said that, uh, you have to wait, uh, as per length. So when you determine the base free flow speed and the first, uh, what your detriment is, the base free-flow speed, uh, for each of the segments, you have to have it for each of the segments, and then you can aggregate it up to the facility. You can aggregate it up to the facility and you can weight by length. So each of the segment lengths you have, and then maybe, um, number of segments in the facility. So it's a simple weight and, um, a weighted average of, uh, developing the basically flow speed. Similarly. For the travel speed, you do the same thing. You have the travel speed for the segments weighed by the segment lengths in order to develop the travel speed for the entire facility. So when you do that, you will be able to develop the level of service for your automobile mode. So this is what we were talking about, uh, the optional step of determining the spatial stop rate. Uh, so the spatial, uh, stop rate is nothing but. Uh, the ratio of the stop count to facility length, right? Stop count. So how many times the vehicle stops, uh, based on the length of the segment? So that is what the, um, uh, spatial stop rate is. It relates to the number of full stops. Uh, it is not just a slowing down of the vehicle, but fully coming to a heart, uh, incurred by the average true vehicle. To the total distance traveled in that segment again, right? So the segment length is this much. And if, uh, these are the, uh, base free flow speeds of the segment, then your spacial stop rate, uh, can be determined. Uh, based, uh, multiplying the basically flow speed with that length and divided the cup with the entire length. So that will, uh, that will give you your, uh, spatial stop rate for the facility. And, uh, you could use that as an additional input in determining the level of service. Uh, but what we will show you is that, uh, just using these two, you can develop the automobile level of service. So if you skip. Decide to skip the step three, uh, or what you need to do in the step four is to divide the values Optane from step one and step two, to obtain a percentage value. A VBC ratio is to be calculated by dividing the volume to capacity, right? Uh, uh, capacity of a two way lane and or a one way street or two ways. One lane street or two lane street is fixed. So that is a fixed capacity. Volume is something that you just measure on the street, uh, measure, um, uh, on site. Uh, you divide the volume by the capacity. Uh, you know, the VBC ratio, as long as the BBC ratio is less than one, uh, you use, uh, you use these values of, uh, travel speed and basically flow speed. Uh, to determine the level of service using the table that we have showing you already. So what you can do is give you an example of how to solve, uh, uh, or how to develop a level of service for a street segment, uh, for the automobile mode. Uh, say the question asks you to determine the automobile level of service for a West to East travel direction of a facility using the at cm 2010 methodology. Individual segment lens, basically low speed travel speed, and spatial stop rate for the facility are given below. So for segment one, you have all of this for segment two, you are all the input parameters for segment three of all the products. Now this, this, uh, we have made it easy for you to understand, uh, where we have given you all the parameters, but when you are developing it for your, uh, street off your city, you need to collect these parameters. So you have to actually measure the segment length. You have to measure, uh, the base free flow speed measure, the travel speed, and also optionally measure the, a special stop rate, maybe. So given, uh, given this and given the VVC the issue of 0.8, seven, what would be the, um, level of service for the multimodal multimodal level of service from the point of view of the automobile for this same section of the road? So, uh, now, uh, as there are only three segments as M is three. So what you can do first is to determine the base free flow speed for the facility. Uh, you know, the base free flow speed for each of the segments, you know, the segment lengths and, uh, you divide the segment lens by the, um, based free flow speed for each of those segments. And you get the, uh, uh, free flow speed for the facility. Similarly. Uh, to determine the tribal speed of the facility. Again, you know, each of the lengths, uh, you know, the lengths and the, uh, travel speeds in each of the segments. So you see the travel speed varies by segment at one place. It is 30 know there's 35, then it's 25 and the segment lengths are also different. So what you get is, uh, uh, travel, uh, speed for different tat facility, uh, since you are, uh, you have been given, uh, the, uh, Uh, free flow speeds. Uh, for each of the segments, you can also develop the special, a stop rate. The special stop rate is nothing but a, the length of the segment, the length of the segment times D uh, uh, uh, based free flow speed for each of those segments. And, uh, you have been given that, uh, not the basically flow speed, but you have been given that number of stop rates or the stop rate. For that segment, you have been directly given the stop rate for that segment. So if you're, if you have been directly given this patient stop rate for that segment, all you need to do is you use that special, use that patient stop rate for that segment. Multiply it by the segment length, uh, average, uh, um, submit up, uh, some of the products and divided by the, uh, length of the total segment. And you get your, uh, spatial stop it. However that is, uh, that is, uh, uh, a, an optional step, uh, to determine the travel speed as a, as a percentage of base free flow speed. All you do is you get the divide. The value of you've gotten step two by step one 29.1 is what you've got in step two, uh, 55.2 is what you bought in step one. So you see, you get a value of 52.7, two percentage, and you know that the VBC ratio is. Well at eight seven, which is less than one. And when you now go back to your table, you find out, uh, your, uh, uh, travel speed as a percentage of base flow speed. So this is 52%. So 52% would lie somewhere here. And since your ribeye seat ratio is less than one, less than or equal to one, you go there and you'll see that this particular facility is providing a level of service C uh, when it comes to an automobile motor. Right. So similarly, what we will do in the following lecture is to give you an understanding of how this can be developed for other, uh, uh, for other, uh, modes, uh, offer the same segment, but for different modes. And then you would see that one particular segment, maybe providing a very good level of service. For one mode, but a very poor level of service for the other mode. So that will give you an understanding of why multimodal level of service is very, very important. You cannot have just one value of level of service for a segment or a facility because that segment or a facility is not exclusive. Or the use of only one type of mode, multiple modes are using that segment. Hence you have to have a multimodal level of service for every facility or segment.