Parking planning in this blog refers the issues regarding parking demand estimation, vehicle circulation, and access design.
For public parking for office, resident and shopping centers, the parking planning are usually contemplated for a perceived demand based on the NFA (net floor area) or GFA (gross floor area). And the planning commonly focuses on demonstrating appropriate parking spaces to accommodate the anticipated peak accumulation of cars on a design day.
A logistic delivery center parking appears with different characteristics beside its predetermined parking demand and controlled vehicles arrival and departure time.
More specifically, delivery drivers work with shift and arrive at the parking usually at the short period of time (small time window). In some circumstances, they must additionally switch their own car for a delivery van inside the parking lot. When a larger parking demand occurs, this duty increases the likelihood of parking aisle blockage and congestion.
These characteristics necessitate that planners reform the logistic parking planning objectives, including,
- to guarantee smooth traffic performance during peak periods,
- to optimize the process time,
- to ensure safety and security of internal traffic and pedestrian movements
- to pursue space and cost efficiency
In order to meet these new objectives, two types of analysis should be made to guarantee an efficient planning which Vectio could offer. First, a static analysis is necessary once the parking layout is determined to look at potential conflict areas, internal circulation, turning spaces, and access locations, among other things.
The second analysis focuses on the dynamic behaviors of the parking lot. Next, the microsimulation method is adopted to provide qualitative and quantitative results regarding any parking management strategy and regulations under consideration.
Microsimulation can be constructed and used for parking design based on the following inputs. If not all data is available, default values will be used.
By summarizing the results, we found out there is no absolute good parking design. Depending on a series factor varies, an angled parking maybe superior to vertical one, or the contrary. Those factors include:
- Parking lot topology, for example, at ground level or on multiple levels.
- Size and capacity of the parking lot, for example, number of levels, number of lanes, and lane length.
- Type of access and ramp.
- Traffic rules, for example, one-way or two-way, turning restrictions.
- Parking demand and distribution of arrival times.
- Operational process: number of necessary exchange spaces.
All mentioned elements should be taken into account and thoroughly evaluated through microsimulation for each specific parking lot. Its results can provide numerical figures to help identify the best design.
These output indicators take into account both space utilization efficiency and traffic performance, such as average delay time, total time employed, average speed, harmonic speed, and maximum length of the virtual queue.
Besides that, the microsimulation method also helps to provide following type of analysis.
- Parking Demand Optimization. It can used to provide a sensitivity analysis on parking demand (number of vehicles per shift) based on the parking capacity as input, and traffic performance indicators as output.
- Microsimulations for optimizing parking aisle. This allows to test the different lengths of the aisles to obtain the most optimal and effective length of the aisle.
- Simulations for different circulating options by changing aisle direction. It aims to examine the discrepancy of circulating design inside of parking.
- Simulations for assessing the impacts of any type of parking facility, for example, speed bumps, entrance/exit pole.
- Simulations for mixed traffic situation by combining both vehicles and pedestrians. These results may bright to light possible conflicts and interfere during exchange process.
- Simulations for dispatch with pedestrian movements. With this we can optimize pedestrians walk route for dispatch.
- Access/Egress simulations. A deeper analysis of the access points is recommended, especially when the site has multiple vehicles (e.g., private car, bus, heavy trucks, vans) operating with different dimensions and overlapping work shifts. These simulations can either be done at the access points or at the ramps when moving between different floors of the building.
- Simulation of the behavior of extreme drivers. Together with the regular driving habits, strange and unsafe driving habits can also be mimicked, and the effects on parking safety can be assessed.
Yang Wang | PhD. Transport Planner | Principal Engineer at Vectio
