Complete Streets Concept

• Definition: Designed to enable safe access for all users, including pedestrians, bicyclists, motorists, and public transport.

• User-Centric Design: Safety and comfort for all road users, regardless of age or ability.

Elements of Complete Streets

• Pedestrian Component: Clear areas between the curb and building frontages to facilitate safe pedestrian movement.

• Building and Furnishing: Street furniture and elements like bicycle parking and benches should be designed to avoid encroaching on sidewalks.

• Bicycle Facilities: Inclusion of bikeways within the public right-of-way (ROW).

• Curbside Management: Facilities such as on-street parking, loading zones, and transit shelters that exist between the cartway and sidewalks.

• Vehicle/Cartway: Areas specifically intended for motor vehicle usage, clearly defined in the ROW.

Policies Impacting Urban Form

• Urban Design Policies: These include considerations for driveways, utilities, and stormwater management that affect complete street implementation.

Intersection & Crossing Treatments

• Safety Enhancements: Includes features like high-visibility crosswalks, curb extensions, and pedestrian refuge islands that facilitate safe movements.

Vulnerable Road Users (VRUs)

• Definition: Refers to high-risk road users, notably pedestrians, bicyclists, and motorcyclists.

• Vulnerability Factors: Determined by protections in traffic and task capacity, particularly among young and elderly populations.

Road Safety Audit (RSA)

• Qualitative Evaluation: Assessment of safety conditions in roadway designs, carried out by experienced auditors.

• Design Focus: Evaluations extend beyond infrastructure to include design drawings.

Risk and Exposure

• Exposure: Refers to the state of being subjected to risk based on time, volume, or distance.

• Risk Assessment: Involves evaluating injury rates in relation to exposure metrics, helping to assess the likelihood of accidents.

Geometric Design Parameters

• Key Elements: Includes detailed design of junctions, road markings, roadside equipment, and alignment specifics.

• Considerations: Identify potential hazards from adverse combinations of design elements such as vertical and horizontal alignments.

Types of Roads

• Primary Arterials: High-capacity routes meant primarily for movement between regions with minimal access.

• Secondary Arterials: Serve movement functions while contributing to access.

• Collector Roads: Facilitate local traffic and connect to the arterial network.

• Access Roads: Primarily used for local, residential purposes.

• Pedestrian Areas: Exclude motor vehicles, focusing on foot and bicycle traffic.

Speed and Design Considerations

• Speed Impact on Safety: Higher vehicle speeds reduce reaction time, increasing crash likelihood.

• Design Speed: Influences road design components and must align with road types.

• Actual Speed Influences: Affected by vehicle type, road geometry, driver behavior, and presence of other road users.

Sight Distance Types

• Stopping Sight Distance (SSD): The distance needed to stop before reaching a stationary object at a given speed.

• Passing Sight Distance (PSD): Required distance for safe overtaking maneuvers on two-lane highways.

Horizontal Alignment Techniques

• Curvature: Combination of tangents and circular curves shapes road from the top view.

• Types of Curves: Includes simple, compound, reverse, and broken back curves, with specific definitions and design implications.

Vertical Alignment

• Definition: The profile shape of the road as viewed from the side, created by vertical curves and grades.

• Key Grades: Minimum grades to prevent water stagnation, especially under different pavement conditions.

• Critical Length of Grade: Length limit for trucks negotiating uphills without significant speed loss.

Coordination in Road Design

• Alignments Harmony: Essential that horizontal and vertical alignments are designed together to enhance safety and efficiency.

• Design Considerations: Avoid sharp curves at crests, and ensure smooth transitions to promote driver comfort.

Conclusion

• Geometric Design of Highways & Streets: Aims at visible designs to ensure safe and economical traffic movement while enhancing user experience.