TransitLM / README.md
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metadata
license: cc-by-nc-4.0
task_categories:
  - text-generation
language:
  - zh
tags:
  - transportation
  - route-planning
  - public-transit
  - mobility
  - instruction-tuning
  - benchmark
pretty_name: TransitLM

TransitLM: Dataset Release & Evaluation Protocol

Dataset Description

TransitLM is a dataset for public transit route planning in Chinese urban environments, designed to support training and evaluation of language models that generate structured transit routes from origin-destination information. The full dataset covers four cities: Beijing, Shanghai, Shenzhen, and Chengdu, and includes coordinates, station sequences, transfer structure, line information, and route annotations.

Released Files

File Pattern Content Section
transit-lm-benchmark*-train.csv Anonymized SFT training splits (benchmark-aligned) §2
transit-lm-benchmark*-test.csv Anonymized SFT test splits for task evaluation §2
transit-lm-general-benchmark*-test.csv Real-world benchmark test sets (real station names + coordinates) §1
transit-lm-station-info.csv Static station-level reference information

All released data follows the anonymization principles described in our paper. The sections below explain the data treatment and evaluation protocol for each component.

Overview. We release two parallel test sets that correspond one-to-one, serving different model categories:

  • Anonymized SFT test set (30K samples). For models trained on our anonymized corpus. These models have only seen numeric station IDs and perturbed coordinates, so they must be evaluated in the same representation space.
  • Real-world benchmark (30K samples). For general-purpose LLMs not trained on our data. These models operate with real station names and coordinates and cannot interpret anonymized IDs, so they require unperturbed evaluation data.

This parallel design ensures fair evaluation for both model types while keeping results directly comparable.


1. Benchmark Test Samples

30,000 test examples across three tasks: optimal route generation, preference-aware planning, and multi-route generation.

Data characteristics:

  • Real GPS coordinates without perturbation
  • Real station names in natural language
  • Full route-structural metadata: station sequences, line sequences, transfer points, distances, travel times, and fares

Purpose. This subset is the ground-truth evaluation benchmark for the research community. The CPT/SFT training corpus applies coordinate perturbation, so evaluating general-purpose LLMs on perturbed data would not reflect real-world performance. Unperturbed samples enable fair comparison across models trained on our corpus, tool-augmented LLMs, and any future transit-domain model.

Privacy. These samples contain no user identifiers, no timestamps, and no cross-record linkage. Each is an isolated OD request. All station coordinates and names are already publicly accessible through mapping APIs, so releasing them in benchmark format introduces no additional privacy risk.


2. CPT + SFT Corpus (Anonymized)

13.9M CPT records, 90K SFT training examples, and 30K SFT test examples.

Anonymization

Transformation Method Training Impact
Coordinate perturbation Deterministic hash-based offset, ±100m on a ~500m grid Negligible. Grid-coherent offset preserves spatial structure. Error < 0.1% of mean route length
Station name removal Names removed from station sequences, retaining only numeric IDs None. Topological learning relies on IDs and connectivity

Rationale. Bulk harvesting coordinate-ID mappings from a 13.9M-record corpus could enable unauthorized commercial use. OD coordinates reflect real user trip intentions. Perturbation combined with structural safeguards prevents re-identification.

SFT Test Set

The 30K SFT test samples undergo identical anonymization. See the Overview above for how they relate to the real-world benchmark and which model category uses which test set.

Usability

Despite anonymization, this corpus fully supports continual pre-training for transit topology and spatial reasoning, supervised fine-tuning for all three benchmark tasks, and reproducibility of all paper results.


3. Privacy Architecture

Unlike GPS trajectory datasets such as T-Drive or GeoLife that record continuous multi-day traces enabling re-identification, each record here is an isolated OD planning request with no temporal continuity.

Structural safeguards enforced at the data construction stage:

  • Single calendar day sampling with no timestamps retained
  • User identifiers removed prior to construction, with no linkage key across records
  • Only route-structural metadata released. No demographic attributes, device fingerprints, or PII

These properties make it infeasible to associate records with the same individual or reconstruct mobility patterns, regardless of coordinate perturbation.


4. Why Both Perturbed and Real Data?

Concern Anonymized corpus Benchmark samples
Coordinate privacy ✅ ±100m perturbation prevents bulk harvesting Public data, no new risk
Fair evaluation ❌ Perturbed coordinates disadvantage general LLMs ✅ Real coordinates enable direct comparison
Reproducibility ✅ Full training pipeline reproducible ✅ Standardized community test set
Training utility ✅ < 0.1% spatial error, topology preserved Not used for training

This dual-release design maximizes research utility through reproducible training and fair evaluation, while minimizing privacy exposure by applying perturbation only where data scale creates risk.