Urban elevated Small Vehicle Limited Access Thoroughfare (SVLAT) concept is introduced as a re-envisioned optimization of urban transportation infrastructure due to recent technological trends. The SVLAT arterials are to be installed over urban transportation corridors providing bespoke zero-second wait time non-stop urban transportation for small electric vehicles, bicycles and pedestrians. The article notes the potential for wide pitch spacing of highways, increased modal speed, congestion relief and improved urban experience. Daunting Technical challenges are noted including: regulatory hurdles, fire safety, aerodynamic design, underground interference, design details, vehicle designs, integration with existing transportation networks, and issues yet unknown. Potential high value applications are identified which may provide additional economic incentive including bridges over wide rivers, additional capacity for special venues, mitigating storm recovery and mitigating rising water levels. Auxiliary uses for the structure are noted including cable or pipe routing. Options for the new highway are noted: potential for connection with existing LAT, covering the highway, full self driving, roadway vehicle charging, and integration with above ground malls. The article concludes that since urban small vehicle modal speed will be increased and costs lowered in some applications research into urban elevated SVLAT should be funded. Keywords: highway, elevated, bicycle, electric vehicle, last mile, expressway, thoroughfare13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 2 Daniel Price, P.E. 3 INTRODUCTION Transportation systems design is undergoing rapid change from trends in battery electrification and self-driving. While changes have focused on optimizing existing systems, little attention has been brought to the topic of systemically re-envisioning transportation infrastructure to best utilize the results of these technological trends. This article is intended to hypothetically introduce novel urban non-stop Small Vehicle Limited Access Thoroughfare (SVLAT) systems as a solution, while also philosophically balancing the results of a comprehensive desktop conceptual feasibility study. The SVLAT system is to be a zero-second-per-mile wait time urban highway for small electric vehicles, providing a bespoke level of service that is currently only available to urban automobile users by way of the non-stop Limited Access Thoroughfare (LAT). Improving transportation can dramatically improve liveability in an urban environment. Imagine the following fictional scenario: getting off work in a congested city, wanting to go across town to an event and then travel home for the evening. In this scenario, on a holiday morning these trips via automobile could take 15 minutes. If you took the subway each trip could require 30-45 minutes. However, if you unfolded your bicycle and rode a feeder bicycle lane to a SVLAT highway, you could make each trip in 15 minutes during rush hour. Without the highway, you might choose to not go to the event. We can easily conjecture that any major transportation change will be facilitated by lower cost and higher trip speed. For this conceptual study it is assumed that if both cost and trip speed are indicated to be as good or better than existing alternatives in select applications' then funding for future study is warranted. Also important at the genesis stage, is identification of any technological or regulatory developments which can mitigate problems. Accessibility is a topic that has gained increased focus in recent times, the basis of the proposed concept is to enhance accessibility by dramatically increasing infrastructure for small low cost vehicles, bicycles and pedestrians. [1] SVLAT highways represent a systemic change for urban transportation philosophy and experience, the last systemic change to transportation infrastructure was the LAT highways. Modern urban designers have not encountered a systemic transportation change proposal, therefore, there exists no recent examples for how to proceed. Logically the primary issues and philosophies should be understood and agreed on prior to committing significant funding. This article's primary goal is to philosophically reconcile whether to proceed with funding. This article is also intended as a forest for trees scoping that can encourage researcher into SVLAT and provide funding organizations an overview of how SVLAT research contributes to their overall goals. A proposal to introduce a systemic change to the urban transportation network can initiate very complex discussions that can only be touched lightly upon in a comprehensive overview. Virtually every issue encountered in LAT highway design is needing study for SVLAT systems, therefore there is a paucity of data to facilitate decision making. This issue rich and data poor environment greatly complicates development of this article. In addition, it is very difficult to know what has driven major transportation systems change in the past. Major transportation systems change has been likened to a biological morphological (evolutionary) process where the genesis of change, individual decisions, has been lost in time. [2] Research for bicycles along 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 3 Daniel Price, P.E. 4 traditional roadways is at times able to illustrate key points. Most research for existing systems is not directly applicable to this novel transportation concept, therefore at times statements utilize engineering judgment to make hypothetical observations. It is acknowledged in the future at least some of the statements will be found wanting. This article uses innovative means to develop hypothetical understanding of select primary factors such as average modal speed, highway spacing and cost comparisons in order to illustrate potential outcomes. These hypothetical understandings should be validated through subsequent research. This article, therefore, makes the first small step in a larger process which could systemically alter urban transportation philosophy. This summary presentation is derived from a detailed white paper study by this author. [3] METHODOLOGY This desktop study was funded and performed solely by the author. This article is organized to address two themes. One theme to logically reconcile if the proposal is worthy of further research. The other theme is to develop a forest for trees perspective of challenges, opportunities, and characteristics associated with SVLAT implementation. The first requires numbers derived from literature be found. The second requires narratively painting a highly detailed mind's eye picture of what this proposal entails. Satisfying both themes is necessary when conceptually considering a novel option. In accordance with Project Management Institute recommendations a brainstorming process developed topics for this study. The items were listed and later further described. The process departed from PMI recommendations as the only person available to generate input is the author. However the author has decades of engineering experience, including significant experience with extremely large and complex projects in the industrial realm. Literature investigations were performed mostly at University of Colorado Colorado Springs library to provide technical guidance or provide research derived parameters which could be used to develop critical observations. The literature search was not comprehensive. Since the concept is novel, there is a paucity of applicable research. The best research is for bicycles which is often found wanting because the research was intended for another purpose. Editorial assistance for a prior version of this article was provided by UCCS technical writing support group. AI, Bard, was used in the first drafts to develop outlines from information contained in a prior article version presented at a conference. Later after information was added, AI was employed to draft introduction and conclusions. AI generated text has been extensively edited. Internal traffic studies were performed during rush hour using the google maps trip tool. The study was performed within Houston Texas during approximately 2010. Elevation view sketch study was performed using measured dimensions of a local street, Colfax Avenue along Capitol Hill within Denver, Colorado USA. Sketch studies are commonly used in brownfield industrial projects to assure adequate space prior to project initiation. In all cases estimates are conservative in nature. When developing conclusion statements the accuracy of the estimates was further distanced by careful construction of the concluding statements. For example the capacity estimates derived from the 2 second rule were only used to indicate capacity being similar regardless of speed, actual capacity from the method was not used in the philosophical development.77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 4 Daniel Price, P.E. 5 In addition the purpose of these statements is to point the way for further research which by it's nature should be directed to independently verify the veracity of this paper's final conclusions of increased modal speed and potentially lower costs for select applications. In effect treating these conclusions as hypothesis in future research. If the veracity of these general arguments are verified, as the author believes they will, then it would seem significant research funding for SVLAT should be authorized. Effort was made to include as many observations as possible. The utility of this is to provide a better forest for trees perspective. However, some potential debates such as vehicle classification regulations are bypassed for brevity. A prior version of this article was presented at EVS37 Seoul South Korea April 2024. A copy of the article was provided to conference participants. This article was revised for Transportation Research Board (TRB) format, reference added, edits performed, and outline re-organized for improved flow. No AI was used in the revision process for subsequent TRB submittal. ENHANCING URBAN MOBILITY Adding high speed transportation capacity can be important for enhancing urban mobility. Adding non-stop arterial capacity above existing corridors without significantly interrupting traffic below can add significant capacity and therefore improve urban mobility in an otherwise congested area. Congestion Relief Through Additional Capacity SVLAT highway capacity is not readily estimable. However, capacity is an important economic factor to understand how congestion can be relieved and if costs can be shared by a large number of users. Insight can be gained from drivers’ teaching tools which advises 2 second spacing between vehicles when driving. [4] This 2 second rule advises for all speeds to maintain time to react to conditions ahead. This rule leads the driver to a system of counting car lengths between vehicles depending on speed. The net result is slower highways with the same length vehicles have tighter spacing and approximately the same number of vehicles per hour regardless of speed. However, it is expected SVLAT highways will be mostly utilized by vehicles less vehicle length than LAT systems. Certainly there are significant limitations in using this rule for estimating highway capacity, but it can be observed that to the first approximation faster speed does not necessarily result in higher capacity per lane. Ignoring the reduction in vehicle length for SVLAT , it can be stated that each lane of Class 3 SVLAT should have similar vehicle carrying capacity compared to automobile LAT per lane. Transportation congestion has been noted throughout history and has historically been relieved by adding additional transportation capacity. [2] Therefore it is likely SVLAT systems with a similar capacity as LAT systems will provide significant new transportation capacity for highly congested areas. Thereby SVLAT systems have the potential to relieve a significant amount of congestion. Increasing Average Small Vehicle Modal Speed121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 5 Daniel Price, P.E. 6 Increasing average modal speed for small vehicles is one of the primary benefits identified for the SVLAT system. The non-stop SVLAT system will provide higher average speed than navigating shared streets with the same mode. In addition, there will be cases where average speed compares well with other existing transportation modes. In comparison with urban automobile mode: internal studies indicate routing SVLAT non-stop over an automobile street with many traffic control lights can allow SLVAT users higher average modal speed than the automobile below in many urban areas. This can be true even if the maximum speed SVLAT is less than the maximum speed on the street below. In comparison with mass transit mode: The trip to and from the SVLAT highway is using a vehicle which travels faster than walking to mass transit. In addition, internal studies indicate zero second-per-mile wait time can result in less time on the highway than along many bus or subway lines. Increased modal speed will affect user p