Module 14: Multimodal Facilities on Mohammad Movahedi

Pedestrian Crossing Analysis

Mon, 04 May 2026 00:00:00 +0000

Pedestrian Crossing Analysis

Pedestrian crossing analysis evaluates the geometric design, signal timing, and safety treatments required for pedestrians to cross roadways safely. Key principles are governed by the Manual on Uniform Traffic Control Devices (MUTCD) and the AASHTO Guide for the Planning, Design, and Presentation of Pedestrian Facilities.

Pedestrian Walking Speed and Signal Timing

Signal timing at intersections must provide adequate time for pedestrians to cross the street before conflicting vehicular movements receive a green indication.

ADA Curb Ramps and Accessible Routes

Mon, 04 May 2026 00:00:00 +0000

ADA Curb Ramps and Accessible Routes

Accessibility in the public right-of-way is governed by the Americans with Disabilities Act (ADA) Standards for Accessible Design and the Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way (PROWAG). Geometric engineers must design ramps and routes that comply with strict slope, width, and surface constraints.

Technical Standards for Ramps and Sidewalks

The following parameters represent critical design criteria for accessible routes:

Feature	ADA Standard	PROWAG Standard (Public Right-of-Way)
Max Ramp Running Slope	1:12 ($8.33\%$)	1:12 ($8.33\%$) (Ramps) / Roadway grade (Sidewalks)
Max Ramp Cross Slope	1:50 ($2.0\%$)	1:50 ($2.0\%$)
Min Clear Width	36 inches ($3.0\text{ ft}$)	48 inches ($4.0\text{ ft}$)
Max Vertical Rise (single run)	30 inches ($2.5\text{ ft}$)	30 inches ($2.5\text{ ft}$)
Min Landing Size	60 in $\times$ 60 in ($5\text{ ft} \times 5\text{ ft}$)	60 in $\times$ 60 in ($5\text{ ft} \times 5\text{ ft}$)
Max Landing Slope (any direction)	1:50 ($2.0\%$)	1:50 ($2.0\%$)

Accessible Routes and Passing Zones

Continuous Clear Width: A minimum clear width of 36 inches is required. If the accessible route is narrower than 60 inches, passing zones of at least 60 in $\times$ 60 in must be provided at intervals not to exceed 200 feet.
Protruding Objects: Objects projecting from walls (e.g., signs, telephone booths) must not project more than 4 inches into the path of travel if their lower edge is between 27 inches and 80 inches above the ground.
Grates: If grates are located on accessible routes, they must have spaces no greater than 0.5 inches wide in the direction of flow, and the long openings must run perpendicular to the dominant direction of travel.

Detectable Warnings (Truncated Domes)

Detectable warnings are raised, truncated domes that provide a tactile warning underfoot and for cane users at the transition between pedestrian walks and the roadway.

Bicycle Facility Selection

Mon, 04 May 2026 00:00:00 +0000

Bicycle Facility Selection

Designing safe and effective bicycle facilities requires matching the facility type to the operating speed and traffic volume of the adjacent roadway. Design standards are governed by the AASHTO Guide for the Development of Bicycle Facilities and FHWA guidelines.

Bicycle Facility Classifications

Bicycle facilities are classified based on the level of separation from motor vehicle traffic.

Facility Type	Separation Level	Typical Widths	Application Context
Shared Lanes (Sharrows)	None (bicycles share lane with vehicles)	Standard lane (11 to 14 ft)	Speed $\le 25\text{ mph}$, Volume $< 3,000\text{ ADT}$.
Bike Lane	Visual separation (striped line & markings)	4 ft (no curb, e.g., rural) / 5 ft (adjacent to curb or parking)	Speed $25-30\text{ mph}$, Volume $3,000-7,000\text{ ADT}$.
Buffered Bike Lane	Visual buffer (striped buffer zone, e.g., 2 ft)	5 ft lane + 2 ft buffer	Speed $30-35\text{ mph}$, heavy curb parking or high turnover.
Separated Bike Lane (Cycle Track)	Physical separation (curb, bollards, parking lane)	5 to 7 ft (one-way) / 10 to 12 ft (two-way)	Speed $\ge 35\text{ mph}$, Volume $\ge 7,000\text{ ADT}$, or heavy truck traffic.
Shared Use Path	Complete physical separation (independent alignment)	10 to 12 ft (minimum 8 ft)	All speeds/volumes; accommodates pedestrians and cyclists.

FHWA Facility Selection Framework

The FHWA (Federal Highway Administration) provides a standard framework for selecting the appropriate bicycle facility based on roadway speed and traffic volume.

Shared Use Paths

Mon, 04 May 2026 00:00:00 +0000

Shared Use Paths

Shared-use paths (often called multi-use paths) are physically separated from motorized vehicle traffic and designed for use by bicyclists, pedestrians, runners, and skaters. Design standards are governed by the AASHTO Guide for the Development of Bicycle Facilities.

Design Width and Lateral Clearances

Standard Minimum Width: 10.0 feet under normal conditions.
Preferred Width (High-Volume): 12.0 to 14.0 feet is recommended in areas with heavy mix of pedestrians, runners, and cyclists.
Minimum Width (Low-Volume Exceptions): 8.0 feet may be used only if:
- Bicycle traffic is low (under 100 per day).
- Pedestrian volume is low (under 100 per day).
- Horizontal and vertical alignment provides good sight distance.
- Maintenance vehicles can navigate without damaging shoulders.
Lateral Clearance: A minimum 2.0-foot wide graded shoulder (with a maximum slope of $1:6$) must be maintained on both sides of the path.
Vertical Clearance: A minimum clearance of 8.0 feet is required (preferred 10.0 feet to accommodate maintenance and emergency vehicles).

Grade and Cross Slope Standards

Shared-use paths must be accessible to users with disabilities, bringing them under ADA jurisdiction.

Transit Stop and Bus Operations Basics

Mon, 04 May 2026 00:00:00 +0000

Transit Stop and Bus Operations Basics

Integrating transit facilities into highway design requires balancing traffic flow with passenger safety and accessibility. Design criteria are governed by the AASHTO Guide for the Geometric Design of Transit Facilities on Highways and Streets and TCRP (Transit Cooperative Research Program) guidelines.

Bus Stop Configurations

There are three primary on-street bus stop configurations:

1. Curbside Stop (In-Lane Stop)

Buses stop directly in the travel lane next to the curb.