Vertical transportation planning is one of the most technically demanding elements of building design, and one of the most consequential. A lift system that is undersized for the building’s population will create queuing problems that persist for the building’s entire operational life. One that is oversized will waste valuable floor space in the core and impose unnecessary capital cost on the project. Getting the sizing right — and getting it right at the design stage, when there is still the opportunity to adjust — depends on rigorous traffic analysis conducted with tools capable of modelling the complexity of the system accurately.
Rigorous lift traffic analysis requires both the right methodology and the right software. The methodology — simulation-based traffic modelling calibrated against appropriate performance criteria for the building type — is well-established in professional guidance. The software to implement it effectively has evolved considerably in recent years, with modern platforms offering capabilities that were not practically accessible to most building professionals even a decade ago.
The Fundamentals of Lift Traffic Analysis
Lift traffic analysis begins with an understanding of the building’s population and how that population will move through the building at different times of day. For an office building, the dominant challenge is the morning up-peak: the period, typically between 8:00 and 9:30am, when a large proportion of the building’s population arrives simultaneously and places maximum demand on the lift system. The system must be sized to handle this peak without creating waiting times that exceed the performance standards appropriate for the building type.
Handling capacity — the percentage of the building’s population that the lift system can transport per five-minute period — is the primary performance metric for up-peak analysis. Average waiting time is the secondary metric, typically expressed as the average time from pressing the call button to the lift arriving. The relationship between these two metrics and the building’s population, floor layout, and lift configuration is complex and non-linear, which is why simplified calculation methods struggle to predict performance accurately for anything other than straightforward standard-profile buildings.
CIBSE’s Guide D: Transportation Systems in Buildings provides the performance benchmarks and analytical methodology that professional lift traffic analysis should follow, covering the full range of building types from commercial offices and residential towers to hotels, hospitals, and mixed-use developments. These benchmarks are the reference against which any traffic analysis software should be calibrated.
How Simulation Improves on Calculation
The advantage of simulation over calculation is most apparent in buildings where the standard assumptions of simplified calculation methods do not hold. Non-uniform floor populations, where some floors have significantly higher occupancy than others, affect performance in ways that average-floor-population calculations do not capture. Multiple entry floors, where passengers join the system at levels other than the ground floor, create traffic patterns that conventional analysis methods were not designed to model.
Destination dispatch control systems — where passengers specify their destination floor at the lobby call point rather than simply pressing an up or down button — change the traffic dynamics of a lift group in ways that conventional simulation models struggle to represent accurately. The grouping of passengers with common destinations into the same car, which reduces the number of stops per trip and increases handling capacity, requires a simulation model specifically designed for this control mode to predict performance correctly.
Modern simulation software that is built around these complexities from the ground up, rather than attempting to extend conventional models to cover them, produces substantially more accurate performance predictions for the buildings and systems where these factors apply. This accuracy is not merely of academic interest — it directly affects the design decisions made on the basis of the analysis and the real-world performance of the building’s lift system for decades after construction.
The Role of Lift Design Software in the Building Design Process
Lift design software serves the building design process at multiple stages, each with different requirements and different implications for the design decisions that follow.
At the concept stage, traffic analysis software helps establish the basic parameters of the lift core: the number of lift shafts required, their approximate dimensions, and the relationship between core size and building performance. This information is essential for the architect to design a core that is both technically adequate and spatially efficient, and it needs to be available early enough to influence the fundamental planning decisions that determine the building’s organisation.
At the detailed design stage, more rigorous simulation supports the specification of the lift system: the exact number and arrangement of lifts, their capacity and speed, the control system type, and the performance guarantees that can be incorporated into the lift contract. The automated reporting capabilities of modern software produce the professional documentation that supports this specification work.
At the tender and procurement stage, the traffic analysis provides the evidential basis for evaluating alternative lift supplier proposals. A supplier who proposes a different configuration from the specified design can be evaluated on the basis of a traffic analysis of their proposed system, providing an objective performance comparison that protects the client’s interests.
What the Best Lift Design Software Delivers
The best lift design software platforms go beyond traffic simulation to provide an integrated design workflow that covers the full range of outputs the building professional needs. Expert system functionality that optimises the lift configuration automatically — testing thousands of alternatives to identify the solution that best meets the building’s performance requirements within specified space and cost constraints — transforms what would otherwise be an iterative, time-consuming manual process into a rapid, comprehensive analysis.
3D visualisation that renders the movement of passengers and lift cars in a building model provides both a powerful design tool and a compelling client presentation format. The ability to demonstrate visually how the proposed lift system will handle peak demand — showing colour-coded waiting times, queue formation, and car movement patterns — communicates performance in a way that tables of numbers alone cannot achieve.
Final Thoughts
Lift traffic analysis and lift design software together form the technical foundation of effective vertical transportation planning. Investing in the right tools and methods at the design stage is the most reliable way to ensure that a building’s lift system delivers the performance its occupants expect throughout the building’s operational life. For professionals exploring the capabilities of modern AdSimulo and comparable platforms, the starting point is understanding what the software produces and how its outputs connect to the design decisions that determine real-world performance.
