======Street Lane Widths=====

This page attempts to lay out the various layers of standards, requirements, ordinances, etc. that lead street and road designs in [[city-of-lynchburg|Lynchburg, Virginia]] to use the lane widths that they do, as well as some alternative standards that exist.

=====AASHTO=====

====A Policy on Geometric Design of Highways and Streets, 7th Edition (used by Lynchburg)====

    * 5.3 Local Streets in Urban Areas
        * 5.3.2.1 Width of Traveled Way
            * "Lanes for moving traffic preferably should be **10 to 11 ft [3.0 to 3.3 m]** wide, and in industrial areas they should be **12 ft [3.6 m]** wide. Where the available or attainable width of right-of-way imposes severe limitations, **9-ft [2.7-m]** lanes can be used in residential areas, and **11-ft [3.3-m]** lanes can be used in industrial areas. Added turning lanes where used at intersections should be at least **9 ft [2.7 m]** wide, and desirably **10 to 12 ft [3.0 to 3.6 m]** wide, depending on the percentage of trucks. Where bicycle facilities are included as part of the design, refer to the AASHTO //Guide for the Development of Bicycle Facilities// (6).
        * 5.3.2.2 Number of Lanes
            * "On residential streets where the primary function of the street is to provide access to adjacent development and foster a community environment, at least **one** unobstructed moving lane must be provided even when parking occurs on both sides. The level of user inconvenience occasioned by the lack of two moving lanes is remarkably low in areas where single-family units prevail. Local residential street patterns are such that travel distances are less than 0.5 mi [1 km] from the trip origin to a collector street. In multifamily-unit residential areas, a minimum of **two** moving traffic lanes to accommodate opposing traffic may be desirable. In many residential areas, a minimum roadway width of **26 ft [8 m]** is needed where on-street parking is permitted. This curb face-to-curb face width of **26 ft [8 m]** provides a **12 ft [3.6 m]** center travel lane that provides for the passage of fire trucks and two **7-ft [2.2-m]** parking lanes. Opposing conflicting traffic will yield and pause in the parking lane area until there is sufficient width to pass."
    * 6.3 Collectors in Urban Areas
        * 6.3.2.1 Width of Roadway
            * "The width of a collector street should be planned as the sum of the widths of the ultimate number of lanes for moving traffic, parking, and bicycles, including median where appropriate. Lanes within the traveled way should range in width from **10 to 12 ft [3.0 to 3.6 m]**. In industrial areas, lanes may be **12 ft [3.6 m]** wide except where lack of space for right-of-way imposes severe limitations; in such cases, lane widths of **11 ft [3.3 m]** may be used. Added turning lanes at intersections, where used, should range in width from **10 to 12 ft [3.0 to 3.6 m]**, depending on the volume of trucks. Where shoulders are provided, roadway widths in accordance with table 6-5 should be considered. Additional guidance on the width of roadways used by transit vehicles can be found in the AASHTO //Guide for Geometric Design of Transit Facilities on Highways and Streets (8)//."
        * 6.3.2.2 Number of Lanes
            * "**Two** traffic lanes are sufficient for most collector streets. In some instances, in commercial areas where there are intersection and midblock left turns, it may be advantageous to provide additional left-turn lanes or **a** continuous two-way left-turn lane in the center of the roadway. Bicycle lanes are often provided on collector streets to create continuous bicycle networks in the community. The number of lanes to be provided on collector streets with high traffic volumes should be determined from a capacity analysis. This analysis should consider anticipated transportation modes, and both intersections and midblock locations in assessing the ability of a proposed design to provide the desired level of service for all users. Such analyses should be made for the future design year traffic volume by using the procedures in the most recent edition of the //Highway Capacity Manual (19)// or other appropriate traffic analysis tools. For further information, see Section 2.4, "Highway Capacity," and the FHWA //Traffic Analysis Tools// website //(11)//,"
    * 7.3 Arterials in Urban Areas
        * 7.3.3.2 Lane Widths
            * "Lane widths on through travel lanes may vary from **10 to 12 ft [3.0 to 3.6 m]**. Lane widths of **10 ft [3.0]** may be used in more constrained areas where truck and bus volumes are relatively low and speeds are less than 35 mph [60 km/h]. Lane widths of **11 ft [3.3 m]** are used quite extensively for urban arterial street designs. The **12-ft [3.6-m]** lane widths are desirable, where practical, on high-speed, free flowing, principal arterials."
        * 7.3.3.4 Number of Lanes
            * "The number of lanes varies, depending on traffic demand, presence and needs of other users, and availability of the right-of-way, bu the typical range for arterials in urban areas is **four to eight** through lanes in both directions of travel combined. Many minor arterials may have **two** through-travel lanes, **one** in each direction. A capacity analysis for all users should be performed to determine the proper number of lanes in consideration of the space needed to accommodate all users of the right-of-way. In addition, roadways are sometimes widened through intersections by the addition of **one or two** auxiliary lanes to accommodate turning vehicles. Section 2.4 presents additional information on capacity analysis."

====Guide for the Development of Bicycle Facilities, 4th Edition (probably used by Lynchburg)====

    * 4.6.4 Bicycle Lane Widths
        * "Bicycle lane widths should be determined by context and anticipated use. The speed, volume, and type of vehicles in adjacent lanes significantly affects bicyclists' comfort and desire for lateral separation from other vehicles. Bike lane widths should be measured from the center of the bike lane line. The appropriate width should take into account design features at the right edge of the bicycle lane, such as the curb, gutter, on-street parking lane, or guardrail. Figure 4-13 shows two typical locations for bicycle lanes in relation to the rest of the roadway, and the widths associated with these facilities."
        * "As discussed in the previous chapter, a bicyclist's preferred operating width is **5 ft (1.5 m)**. Therefore, under most circumstances the recommended width for bike lanes is **5 ft (1.5 m)**. Wider bicycle lanes may be desirable under the following conditions"
        * "Adjacent to a narrow parking lane (7 ft [2.1 m]) with high turnover (such as those servicing restaurants, shops, or entertainment venues), a wider bicycle lane (**6-7 ft or 1.8-2.1 m**) provides more operating space for bicyclists to ride out of the area of opening vehicle doors."
        * "In areas with high bicycle use and without on-street parking, a bicycle lane width of **6 to 8 ft (1.8-2.4 m)** makes it possible for bicyclists to ride side-by-side or pass each other without leaving the lane."
        * "On high-speed (greater than 45 mph [70 km/h] and high-volume roadways, or where there is a substantial volume of heavy vehicles, a **wide** bicycle lane provides additional lateral separation between motor vehicles and bicycles to minimize wind blast and other effects."

=====NACTO=====

====Urban Street Design Guide (not used by Lynchburg)====

    * Lane Width **[[https://nacto.org/publication/urban-street-design-guide/street-design-elements/lane-width|Summary]]**
        * " Lane widths of **10 feet** are appropriate in urban areas and have a positive impact on a street's safety without impacting traffic operations. For designated truck or transit routes, one travel lane of **11 feet** may be used in each direction. In select cases, narrower travel lanes (9–9.5 feet) can be effective as through lanes in conjunction with a turn lane."

=====Virginia DHCD=====

====Virginia Statewide Fire Prevention Code 2015 (adopted by Lynchburg ordinance)====

    * 503.2.1 Dimensions
        * "Fire apparatus access roads shall have an unobstructed width of not less than 20 feet (6096 mm), exclusive of shoulders, except for approved security gates in accordance with Section 503.6, and an unobstructed vertical clearance of not less than 13 feet 6 inches (4115 mm). Exception: Fire apparatus access roads exclusively serving single family dwelling or townhouse developments that are fully sprinklered, as provided for in Sections R313.1 or R313.2 of the International Residential Code, shall have an unobstructed width of not less than 18 feet (5486 mm), exclusive of shoulders."

**Assume that any quotations on this page are under copyright of the original author. They are copied here for the purpose of study and criticism, which constitutes fair use.**

=====Lynchburg, Virginia=====

====Code of Ordinances====

    * [[https://library.municode.com/va/lynchburg/codes/code_of_ordinances?nodeId=CH24.1SUOR_ARTVIGERE_S24.1-30ST|Section 24.1-30]](g) Minimum widths
        * "The minimum width of proposed streets, measured from lot line to lot line, shall be in accordance with regulations established by the City of Lynchburg, Manual of Specifications and Standard Details. Street widths are typically but not always **50 feet** in width. The street width shall be based on the post development average daily traffic and shall be of sufficient width to accommodate the typical street cross section designated therein. If an existing street is to be utilized for access and such street is not of sufficient width per the criteria of the City of Lynchburg Manual of Specifications and Standard Details and the subdivider owns property on both sides of the street, then provisions shall be made on the plat to widen the street to accommodate the standard street width. Should the subdivider abut on only one side of an existing street, then provisions shall be made on the plat to widen one-half of the street to accommodate the standard street width as measured from the centerline of the existing street."
    * [[https://www.lynchburgva.gov/452/Manual-of-Specifications|Manual of Specifications and Standard Details]]
        * 25.01 TYPICAL CURB and GUTTER STREET SECTION
            * {{ :25-01-1.pdf |25.01 (page 1)}}
            * {{ :25-01-2.pdf |25.01 (page 2)}}