Up Peak Analysis
July 1, 2026
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Up peak analysis is the study of a fifteen-minute window that, for most office buildings, sizes the entire lift installation. Between roughly 8:45 and 9:00 a.m., a large share of the population arrives at the ground floor and wants to go up. If the lifts cope with that, they cope with the rest of the day. Up peak analysis is how you find out whether they will, and it usually decides the whole design.
The up-peak is the hardest traffic condition a passenger lift group faces, which is why up peak analysis is the cornerstone of lift sizing. Demand is one-directional and intense: everyone is travelling up from a single terminal floor at once. Cars fill at the lobby, make their delivery stops, and return empty, which is the least efficient cycle a lift can run. If the group can clear the up-peak to target, almost every other period of the day is easier.
That is why traffic engineers treat up peak analysis as the governing case for sizing. Down-peak, when people leave, spreads over a longer period. Interfloor traffic during the day is lighter. The morning arrival surge is the stress test, and a lift group is specified to pass it.
Up-peak analysis of the building produces the same core metrics as any traffic study, read specifically for the arrival window:
A design is judged by whether these sit within target. A common benchmark for a good-quality office is a handling capacity around 12% or more of the population in five minutes, with an interval comfortably under 30 seconds, though the exact targets depend on the building’s grade.
The traditional method behind this analysis calculates round trip time for a single car carrying a typical up-peak load, then derives interval and handling capacity. Round trip time accounts for the number of stops a full car is likely to make, the time lost at each stop for doors and passenger transfer, and the travel time over the building’s height. It is a well-established calculation and a sound first pass for a conventional building.
The limitation is that round trip time calculation assumes an idealised, evenly distributed load. Real arrivals cluster, and cars do not fill to a neat average. Simulation-based the analysis models the actual stream of arriving passengers and the dispatch logic that assigns them to cars, capturing the lumpiness the calculation smooths away. For buildings with destination dispatch or multiple zones, simulation is the only method that represents the up-peak honestly.
The value of the up-peak study is diagnostic. When the peak fails its targets, the metrics point to the cause. A long interval with adequate capacity suggests too few cars. Adequate interval but low handling capacity suggests cars that are too small. A long journey time in a tall building suggests insufficient speed. Each symptom maps to a lever, and each lever can be tested in software before it costs anything on site.
AdSimulo automates exactly this search. You set the building population, tenancy and target level of service, and its Expert System runs thousands of up-peak simulations to return the configuration that meets the target, rather than leaving you to adjust and rerun by hand. The real-time 3D visualisation then shows the up-peak playing out, the lobby queue forming and clearing, so the diagnosis is visible, not just tabulated.
The up-peak governs most offices, but not every building. In buildings with heavy lunch-time movement, two-way traffic can be the harder case, and a design tuned only for the up-peak may disappoint at midday. The discipline is to size on the up-peak through up-peak analysis of the building and then verify the other periods, rather than assuming the morning case covers everything. A modern study checks up-peak, lunch-time two-way and down-peak and confirms the design passes the governing one.
The up-peak targets used in UK practice trace back to the recommendations in CIBSE Guide D, the standard reference for transportation systems in buildings, which sets out the service criteria and population assumptions traffic engineers design to. The CIBSE knowledge portal is the authoritative source for the current guidance. Designing to those benchmarks is what lets a consultant defend a configuration to a client or a planning authority.
Treat the up-peak as the governing case, size the group to clear it within target through this analysis, and then verify the other traffic periods. To run an the analysis that searches automatically for the configuration meeting your targets, see the lift traffic analysis workflow.
Because traffic is intense and one-directional. Everyone travels up from one floor at once, so cars fill at the lobby, make multiple delivery stops and return empty, the least efficient cycle. A group that clears the up-peak handles easier periods comfortably.
For a good-quality office, an interval comfortably below 30 seconds is typical, with premium buildings targeting nearer 25 seconds or less. The right figure depends on the building’s grade and the client’s brief.
Not always. In buildings with heavy midday movement, lunch-time two-way traffic can be the harder case. Good practice sizes on the up-peak and then verifies the other periods rather than assuming the morning case is always worst.
For a conventional building, a round trip time calculation gives a reasonable up-peak result. For destination dispatch, zoning or sky lobbies, simulation is needed because those systems behave in ways calculation cannot capture.
