Bus-Conditioned Zero-Shot Trajectory Generation via Task Arithmetic

Fuente: arXiv
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Main Authors: Liu, Shuai, Cao, Ning, Chen, Yile, Jiang, Yue, Cong, Gao
Format: Preprint
Published: 2026
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_version_ 1866915796976926720
author Liu, Shuai
Cao, Ning
Chen, Yile
Jiang, Yue
Cong, Gao
author_facet Liu, Shuai
Cao, Ning
Chen, Yile
Jiang, Yue
Cong, Gao
contents Mobility trajectory data provide essential support for smart city applications. However, such data are often difficult to obtain. Meanwhile, most existing trajectory generation methods implicitly assume that at least a subset of real mobility data from target city is available, which limits their applicability in data-inaccessible scenarios. In this work, we propose a new problem setting, called bus-conditioned zero-shot trajectory generation, where no mobility trajectories from a target city are accessible. The generation process relies solely on source city mobility data and publicly available bus timetables from both cities. Under this setting, we propose MobTA, the first approach to introduce task arithmetic into trajectory generation. MobTA models the parameter shift from bus-timetable-based trajectory generation to mobility trajectory generation in source city, and applies this shift to target city through arithmetic operations on task vectors. This enables trajectory generation that reflects target-city mobility patterns without requiring any real mobility data from it. Furthermore, we theoretically analyze MobTA's stability across base and instruction-tuned LLMs. Extensive experiments show that MobTA significantly outperforms existing methods, and achieves performance close to models finetuned using target city mobility trajectories.
format Preprint
id arxiv_https___arxiv_org_abs_2602_13071
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Bus-Conditioned Zero-Shot Trajectory Generation via Task Arithmetic
Liu, Shuai
Cao, Ning
Chen, Yile
Jiang, Yue
Cong, Gao
Machine Learning
Artificial Intelligence
Mobility trajectory data provide essential support for smart city applications. However, such data are often difficult to obtain. Meanwhile, most existing trajectory generation methods implicitly assume that at least a subset of real mobility data from target city is available, which limits their applicability in data-inaccessible scenarios. In this work, we propose a new problem setting, called bus-conditioned zero-shot trajectory generation, where no mobility trajectories from a target city are accessible. The generation process relies solely on source city mobility data and publicly available bus timetables from both cities. Under this setting, we propose MobTA, the first approach to introduce task arithmetic into trajectory generation. MobTA models the parameter shift from bus-timetable-based trajectory generation to mobility trajectory generation in source city, and applies this shift to target city through arithmetic operations on task vectors. This enables trajectory generation that reflects target-city mobility patterns without requiring any real mobility data from it. Furthermore, we theoretically analyze MobTA's stability across base and instruction-tuned LLMs. Extensive experiments show that MobTA significantly outperforms existing methods, and achieves performance close to models finetuned using target city mobility trajectories.
title Bus-Conditioned Zero-Shot Trajectory Generation via Task Arithmetic
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.13071