Development Control / Encroachment PDF

# Development Control / Encroachment Planning is a constantly changing process. The difficulty is to control the degree of change so that the various inter-related elements can still operate efficiently. In land use terms this is usually achieved (with varying degrees of success) through the contr...

# Development Control / Encroachment Planning is a constantly changing process. The difficulty is to control the degree of change so that the various inter-related elements can still operate efficiently. In land use terms this is usually achieved (with varying degrees of success) through the control of existing or new development and prevention of uncontrolled parking, illegal accesses and spread of unauthorized commercial activity. The main points to consider are that: - Strict control of roadside hoardings and advertisement boards is required - Land-use and highway requirements change over time so some spare capacity should be designed into road networks to enable such changes to be accommodated without detrimental effects upon road safety - Building regulations should include 'building line' specifications to control roadside development - If development control standards permit the growth of activities to encroach onto the transport corridor, additional countermeasures may be required to maintain a safe level of service to the community as a whole - Strong development control can only prevent encroachment onto roads if there alternative locations for commercial activities to be undertaken; and, - Unauthorized development such as roadside advertising boards, illegal accesses and market stalls which create unsafe traffic conditions should be removed as soon as possible and the sites monitored to prevent their reappearance. # Access Control Access control applies to both vehicular and pedestrian traffic. Local practices have shown different practices in treating access to developments such as: - Provision of elevated pedestrian walkways or underpasses to separate people from road traffic. Oftentimes, these facilities have direct access to respective developments - Driveways should not lead directly to a high-speed road facility as this may create conflict and compromise safety. Good management of access to roadside properties on arterial roads can reduce conflict between through traffic and local traffic, for example by the provision of service roads - Large parking facilities should locate entrance/exits away from high-speed roads, but with good access circulation leading to high-speed roads - Expressway ramps should be carefully planned to reduce conflict with local vehicle and pedestrian traffic - On new roads of district distributor level or higher, direct frontage access should only be permitted in exceptional circumstances - The number of direct accesses onto main roads should be minimized and service roads or collector roads used to bring traffic to a single T-junction at the main road - No access should be permitted at potentially dangerous locations (e.g. at road intersections, or on bends with poor visibility); and, - In all cases, each class of road should intersect only with roads in the same class or one immediately above or below it in the hierarchy. # Traffic Impact Assessment (TIA) Recent developments in transportation research in the Philippines have resulted in the formulation of a TIA Handbook. This handbook was prepared by the National Center for Transportation Studies (NCTS) in order to standardize the conduct of TIA. In addition, it is worth giving more emphasis on road safety as well as the traditional subjects such as volume control, traffic forecasts, demand management, and congestion mitigation. ## Subjects for Consideration Some interesting subjects for consideration in the TIA is the interface between land use development and traffic. This should be reviewed against the guidelines of the Housing and Land Use Regulatory Board (HLURB). Parking demand and restrictions should also be strictly followed as mandated by the National Building Code. Preferably, parking demand should be based on local parking indices and not on international practices since local traffic conditions vary much from other countries' experiences. Pedestrian considerations should also be given more weight in the planning stage. ## Road Safety Importance Road safety is given importance in the proposed TIA guidelines. The general scope of works on the proposed guidelines cover the following: - **Transportation Improvement** - **Road Geometry** - **Traffic Safety** - **Site Circulation and Parking** - **Transportation facilities related to public transport, bicycle, and pedestrian travel** - **Transportation demand management** - **Neighborhood traffic and parking management** - **Funding for countermeasures** ## Standards of Significance Likewise, the NCTS TIA guidelines have listed the standards of significance for traffic impacts of a project: - If the projected traffic will cause the existing intersection or highway roadway levels of service to drop below an acceptable level of service - If the projected traffic will contribute to the increase in traffic along arterials or at intersections currently operating at unacceptable levels - If the project design does not have adequate parking or circulation capacity to accommodate an increase in traffic - If the traffic increase or roadway design will result in safety concerns - If the project does not include adequate provision for bicycle, pedestrian, or public transport access # Road Design Parameters ## Speed Management ### Design Speed The choice of an appropriate design speed for a road project is important to ensure a safe design. When choosing a design speed, the following factors need to be considered: - **Function of the road.** An arterial road such as a national highway would generally have a higher design speed than a local road - **Anticipated operating speed.** For example, a national highway in an area with steep terrain would generally have a lower design speed (i.e., smaller radius curves) than a national highway in flat terrain where higher speeds would generally be anticipated, and hence large radius curves adopted. In these examples, the anticipated operating speed of the new facility (that may include improved alignment and road surface), should form the basis for determining an appropriate design speed, rather than the operating speed of the existing road - **Anticipated speed limit.** When considering the design speed along a route, it may also be necessary to adopt a different design speed for different sections of the road as circumstances change. For example, within a town or on the road section between towns - **Economics.** The implications relating to cost of construction. ### Speed Implications Research shows that lower speeds lead to fewer and less serious crashes. There are two reasons for this: - At higher speeds, a rider or driver has less time to react to a situation and therefore there is a greater likelihood that an error will result in a crash - The momentum and kinetic energy of a vehicle increases rapidly with speed. The sudden dissipation of this energy in a crash means that the injury to occupants is more severe. Therefore, a carefully planned speed limit regime can make a significant contribution to road safety. ### Current Speed Limits The current speed restrictions are set out in Chapter IV - Traffic Rules, in Republic Act No. 4136 'Land Transportation and Traffic Code.' The rules indicate that a motorist shall drive at a safe speed determined by the driver based on the road environment and conditions. There are however maximum allowable speeds for different road environments: - On open country roads with no "blind corners" not closely bordered by habitation, the maximum speed for passenger cars and motorcycles is 80kph and for motor trucks and buses, 50kph. - On "through streets" or boulevards clear of traffic, with no 'blind corners', when so designated, the maximum speed for passenger cars and motorcycles is 40kph and for motor trucks and buses, 30kph. - On city and municipal streets, with light traffic, when not designated 'through streets', the maximum speed for passenger cars, motorcycles, motor trucks and buses is 30kph. - Through crowded streets, approaching intersections at "blind corners", passing school zones, passing other vehicles which are stationary, or for similar dangerous circumstances, the maximum speed for passenger cars, motorcycles, motor trucks and buses is 20kph. - Where it is determined that a road should have a different speed restriction to that indicated above, then specific speed restriction signs should be installed to inform motorists. The following sections describe where certain speed restrictions could be appropriate. #### High Risk Pedestrian Areas - 40 kph Vulnerable road users, especially pedestrians, are particularly vulnerable at higher speeds. The graph below based on international research shows the risk of a pedestrian fatality if hit by a vehicle at different speeds. [Image description - A graph showing the relationship between the speed of a vehicle and risk of fatality for pedestrians. The risk of pedestrian fatality increases as speed of the vehicle increases. The x-axis shows the impact speed (km/h) and the y-axis shows the risk of fatality (%).] For instance 25% of people struck by a vehicle travelling at 40 kph would suffer fatal injuries. At 50 kph, this risk increases to 85%. Therefore, a speed limit of 40 kph or lower would be appropriate in areas where there is high pedestrian activity, such as in city center areas. A 40 kph speed limit would also be appropriate on roads where there are no footpaths and pedestrians are required to walk on the road. #### Low risk pedestrian areas - 60 kph On roads through built-up areas where there are not so many pedestrians, it is appropriate to allow motorized traffic to travel more quickly. The following picture shows the type of environment where 60 kph may be appropriate. Although this road is carrying vulnerable road users, they have a separate lane to travel in. [Image description - A drawing of a road with a separated lane for non-motorised vehicles on the left and motorised vehicles on the right of the image. Non-motorised vehicles include bicycles and pedestrians.] ## Speed Restriction Signs Good speed management practice depends on speed limit signs being placed in visible locations and repeated frequently enough for motorists to be certain of which speed zone they are in. At the start of a new speed zone, a speed limit sign should be erected on the left and right sides of the road. Then within the first kilometer, there should be two (2) farther pairs of repeater speed limit signs. After that, repeater signs should be placed at one kilometer spacing. Repeater signs should also be placed before and after all major intersections to confirm the speed limit to all traffic turning into the road being considered. ### Poor Road Standards If the standard of the road geometry or its surface is poor, then it may be appropriate to adopt a lower speed limit than would ordinarily apply until such time that the road improvements can be made. The lower speeds compensate for the hazardous conditions of the road. An 80kph or 90kph speed limit may also be appropriate on lower standard expressways. For instance, the concrete plant cylinders on the side of the expressway as shown in Figure 8.3 are a serious road hazard within the clear zone, which could cause injury to the occupants of an out of control vehicle. If this roadside hazard cannot be removed or protection for vehicles provided, the speed limit should be restricted to reduce the risk to motorists and riders. [Image description - A diagram of a road with a wide median and concrete barriers on the outer edges of the road. The text "Figure 8.3: High Speed Road with Wide Median" is below the diagram.] ## Road Capacity Road Capacity, as defined in the U.S. Highway Capacity Manual (HCM), is the maximum number of vehicles, which have a reasonable expectation of passing over a given section of a lane or a roadway in one direction or in both directions during one hour under prevailing road and traffic conditions. Generally, road capacity with respect to road sections is measured in terms of 'level-of-service'. This is designated with letters 'A' to 'F', with 'A' the most ideal condition and 'F' the saturated condition where volume is equal to the road capacity. In regard to intersections, capacity is generally measured in terms of 'degree of saturation.' The capacity of a route can be affected by the following factors: - Number of Lanes - Lane and shoulder width - Terrain and road gradient - Traffic composition - Side friction such as the presence of road furniture and pedestrians - Intersection capacity (priority of movements, traffic signal phasing, number of lanes etc.). Ideal capacity of a road is 2,000 vehicles/hour (vph). However, based on several surveys conducted in Metro Manila for various infrastructure projects, it was found that the maximum volume is achieved only at a level of 1,400vph on expressways and 1,100 for urban arterials. In the design stage of a road project, appropriate capacity should be established to ensure satisfactory operation. In establishing the capacity of the road, actual traffic surveys as well as investigation of future use is required to ensure that safety is not compromised once the facility is in operation. ## Traffic Forecasts Experiences in the Philippines indicated that traffic forecasts for expressways (tolled facilities) are usually optimistic. This may be seen as a factor to boost revenue forecasts to make the road appear more interesting to investors. The opposite can be true in planning urban arterials as forecasts are often below actual traffic counts once the facility is in operation. The latter has more impact on traffic safety since it could mean more traffic is using the road than the volume for which it was originally designed. Further, road maintenance is often compromised when traffic exceeds the forecasts (e.g. thickness of pavement, lane width, maintenance budget, etc.).