In dynamic traffic environments, motion forecasting models must be able to accurately estimate future trajectories continuously. Streaming-based methods are a promising solution, but despite recent advances, their performance often degrades when exposed to heterogeneous observation lengths. To address this, we propose a novel streaming-based motion forecasting framework that explicitly focuses on evolving scenes. Our method incrementally processes incoming observation windows and leverages an instance-aware context streaming to maintain and update latent agent representations across inference steps. A dual training objective further enables consistent forecasting accuracy across diverse observation horizons. Extensive experiments on Argoverse 2, nuScenes, and Argoverse 1 demonstrate the robustness of our approach under evolving scene conditions and also on the single-agent benchmarks. Our model achieves state-of-the-art performance in streaming inference on the Argoverse 2 multi-agent benchmark, while maintaining minimal latency, highlighting its suitability for real-world deployment.
Figures & tables
Figure 1: In real-world driving scenes, the available context history for different agents is heterogeneous. Therefore, forecasting models should be able to make accurate predictions for both long-term (brown car) and short-term (green car) contexts, where agents have been observed for a long time or have recently entered the field of view. While existing models often struggle with such varying context lengths, our SHARP is explicitly designed to provide accurate forecasts in such dynamically evolving scenes. Dotted lines indicate the available observations, while transparent paths show the corresponding future trajectory.
Figure 2: To jointly incorporate newly detected agents and long-term agent histories when forecasting motions in evolving scenes, we leverage a streaming-based motion forecasting model. The example at time step t−1 illustrates the standard model pass without streaming context, consisting of separate agent and lane encoders ( fA and fL ), a scene encoder ( fS ), and a trajectory decoder ( fD ) with a streaming refinement module ( fR ). At the next time step t , we integrate the previous scene context Senct−1 via an instance-aware context streamer ( fIA ) and generate auxiliary target-centric features Ct by aggregating scene elements closely around the endpoints of the previous predictions Ft−1 . To improve robustness, we also perform, only during training, a parallel model pass without streaming modules, producing Fchunkt which is used to compute the Lchunk objective.
Figure 3: Comparison of different evaluation setups on a motion forecasting dataset with Ht as historical context and Ft as future for the prediction task. The standard benchmark evaluation only considers a single history/future split per scenario (first row). In our experiments, we test the models at different time steps tpi into the scenario and using varying context lengths Tcli as model input and also evaluating for different future horizons Tfi .
Table 1: Evaluation of streaming-based methods on the AV2 validation set at varying prediction time steps tp and context lengths Tcl . To ensure a fair comparison, we test related work [ 36 , 50 ] using their standard streaming configuration (3 s input windows with 1 s displacement) and only adjust the number of inference passes to vary Tcl . The top block evaluates short observation lengths, while the second block extends the context to achieve streaming processing beyond the standard 3 iterative steps of [ 36 , 50 ] . The third block tests streaming with Tcl = 4 s at different prediction times. The bottom block corresponds to the standard AV2 evaluation. For predictions at tp> 5 s, the evaluation is truncated as only 11 s are available. Further details on the experiment setup are provided in the supplementary material.
Method
Streaming
avgMinADE 1
avgMinFDE 1
actorMR 6
avgMinADE 6
avgMinFDE 6
avgBrierMinFDE 6
FJMP [ 33 ]
✗
1.52
4.00
0.23
0.81
1.89
2.59
Forecast-MAE [ 6 ]
✗
1.30
3.33
0.19
0.69
1.55
2.24
SRefiner [ 45 ]
✗
1.48
3.85
0.19
0.68
1.52
2.21
RealMotion [ 36 ]
✓
1.14
2.87
0.18
0.62
1.32
2.01
DeMo [ 50 ]
✓
1.12
2.78
0.16
0.58
1.24
1.93
SHARP (Ours)
✓
1.03
2.53
0.15
0.56
1.15
1.80
Table 2: Multi-agent benchmark on the AV2 test set. For all metrics lower values indicate better performance, table sorted in descending order by avgBrierMinFDE 6 . For all methods we report results without model ensembling.
Method
Streaming
MR 6
mADE 6
mFDE 6
b-mFDE 6
SIMPL [ 51 ]
✗
0.19
0.72
1.43
2.05
HPTR [ 52 ]
✗
0.19
0.73
1.43
2.03
Forecast-MAE [ 6 ]
✗
0.17
0.71
1.39
2.03
MTR [ 34 ]
✗
0.15
0.73
1.44
1.98
EMP-D [ 30 ]
✗
0.17
0.71
1.37
1.98
GANet [ 40 ]
✗
0.17
0.72
1.34
1.96
Table 3: Single-agent benchmark on the AV2 test set. For all metrics lower values indicate better, table sorted in descending order by brier-minFDE 6 . We report results for published works on the official leaderboard without model ensembling.
Dataset
Tcl
TCF
IA
DT
mADE 6
mFDE 6
b-mFDE 6
5 s
✗
✗
✗
0.74
1.28
1.91
✓
✗
✗
0.64
1.22
1.84
✓
✓
✗
0.63
1.19
1.81
AV2
✓
✓
✓
0.64
1.20
1.82
Val
1 s
✗
✗
✗
1.18
2.57
3.28
✓
✗
✗
1.09
2.49
3.18
Table 4: Ablation study on the impact of our target-centric features (TCF), Dual Training (DT) and Instance-Aware (IA) Context Streaming using varying context lengths ( Tcl ). For each dataset, we compare full-history and partial-history settings. All predictions adhere to the standard evaluation protocol: tp=2s , Tf=3s for AV1 and tp=5s , Tf=6s for AV2.
Method
Streaming
mFDE 1
MR 5
mADE 5
THOMAS [ 16 ]
✗
6.71
0.55
1.33
PGP [ 9 ]
✗
7.17
0.52
1.27
DeMo [ 50 ]
✗
6.60
0.43
1.22
MacFormer [ 13 ]
✗
7.50
0.57
1.21
LAFormer [ 23 ]
✗
6.95
0.48
1.19
Q-EANet [ 5 ]
✗
6.77
0.48
1.18
Table 5: Results on the nuScenes prediction challenge test set. Following the evaluation protocol, we set the model output to K=5 . DeMo [ 50 ] reports nuScenes results without streaming.
Dataset
Input Steps
Tcl
Method
mADE 6
mFDE 6
Argoverse 1
5
0.5 s
POP-H [ 41 ]
0.74
1.10
TSD-H [ 57 ]
0.72
1.04
SHARP (Ours)
0.61
0.96
10
1 s
HiVT-64-FLN [ 46 ]
0.81
1.25
POP-H [ 41 ]
0.70
1.06
TSD-H [ 57 ]
0.67
0.98
Table 6: Comparison to the state-of-the-art varying-length models [ 46 , 41 , 57 ] , following their evaluation protocol.
Appendix figures & tables16 assets
Supplementary material from the paper’s appendix.
Appendix
Table 7: Evaluation of SHARP on the AV2 validation set performed across different context lengths Tcl . Within each group, the prediction time step tp and forecasting horizon Tf are held constant, while the observation length provided to the model is varied. We evaluate predictions at the standard tp=5s , as well as at tp=7s and tp=8s , to study the impact of longer observation lengths on forecasting performance.
Noise Type
Noise Ratio
mADE 6
mFDE 6
b-mFDE 6
Randomized
80%
0.65
1.23
1.85
40%
0.65
1.22
1.84
20%
0.64
1.21
1.83
Set to Zero (no match)
80%
0.65
1.22
1.84
40%
0.64
1.20
1.83
20%
0.64
1.20
1.82
Appendix
Table 8: We evaluate the robustness of our instance-aware context streamer under perturbed instance masks . In the first group, we partially randomize the masks, introducing incorrect correspondences and removing correct ones, resulting in both false positives and false negatives. In the second group, we remove associations by partially setting mask values to zero, producing false negatives while leaving other annotations intact.
Table 9: Evaluation of SHARP in the multi-agent setting on the AV2 validation set at varying prediction time steps tp and context lengths Tcl . The evaluation scope is limited to our method due to missing multi-agent implementation details and code bases for related work [ 36 , 50 ] .
Endpoint Noise (meter)
mADE 6
mFDE 6
b-mFDE 6
U(−5,5)
0.65
1.23
1.85
N(0,3)
0.65
1.23
1.85
U(−3,3)
0.64
1.21
1.83
N(0,1)
0.61
1.20
1.82
U(−1,1)
0.64
1.20
1.83
Clean Data
0.63
1.19
1.81
Appendix
Table 10: We evaluate the robustness of our target-centric features under perturbations of the predicted endpoints used for the token selection. Gaussian ( N ) and uniform ( U ) noise are applied to simulate degradation of predictions during streaming. This setup assesses how our model handles such errors and its ability to recover from inaccurate prior predictions.
Method
Streaming
MR 6
mADE 6
mFDE 6
mmTransformer [ 24 ]
✗
0.11
0.71
1.15
FRM [ 29 ]
✗
-
0.68
0.99
ADAPT [ 1 ]
✗
0.08
0.67
0.95
SIMPL [ 51 ]
✗
0.08
0.66
0.95
HiVT [ 55 ]
✗
0.09
0.66
0.96
R-Pred [ 7 ]
✗
0.09
0.66
0.95
Appendix
Table 11: Results on the Argoverse 1 prediction challenge validation set .
Table 12: We compare our SHARP to DeMo [ 50 ] using short context lengths Tcl of 1 s on the AV2 single-agent validation set.
Table 13: Evaluation of SHARP on extend prediction horizons using the AV2 single-agent validation set. Predictions of the agent’s final position at the end of each scenario are made at varying prediction times tp . Even the initial predictions over long horizons provide reasonable estimates. As the available context Tcl increases and the prediction horizon Tf shortens, the forecasts naturally become more accurate.
Tcl
Loss L Configuration
mADE 6
mFDE 6
b-mFDE 6
2⋅Lstream+1⋅Lchunk
0.66
1.23
1.85
5 s
1⋅Lstream+2⋅Lchunk
0.66
1.24
1.87
1⋅Lstream+1⋅Lchunk
0.66
1.24
1.86
2⋅Lstream+1⋅Lchunk
0.97
2.14
2.82
1 s
1⋅Lstream+2⋅Lchunk
0.87
1.84
2.52
1⋅Lstream+1⋅Lchunk
0.94
2.03
2.70
Appendix
Table 14: We evaluate training SHARP using a weighted dual loss formulation , where the weights allow us to emphasize either long-term or short-term context performance. In our final model, we omit these weights, resulting in equal contributions from both loss terms. Note that this analysis is based on a preliminary experiment conducted with a reduced training schedule.
Table 15: Ablation study on AV2 for long input horizons using our instance-aware context streaming fIA module compared to the standard context relay streaming module proposed by [ 36 ] .
Th
Train Pass at tp
IA
mADE 6
mFDE 6
b-mFDE 6
3 s
{3, 4, 5} s
✗
0.66
1.23
1.84
2 s
2 .. 5 s
✗
0.66
1.24
1.85
1 s
1 .. 5 s
✗
0.64
1.22
1.85
1 s
1 .. 8 s
✗
0.65
1.22
1.84
2 s
2 .. 5 s
✓
0.66
1.22
1.83
1 s
1 .. 5 s
✓
0.65
1.21
1.83
Appendix
Table 16: Ablation study on training our approach with varying input window sizes ( Th ) and different numbers of back-propagation passes per scenario, with and without our instance-aware context streaming (IA). The displacement during consecutive train passes is 1 s for all experiments. The first row reports training results for our SHARP architecture using the baseline streaming setup of [ 36 ] . Reducing the input window size Th enables performing more back-propagation passes over each scenario. However, existing streaming mechanisms fail to fully exploit this potential, which is effectively unlocked by our instance-aware context streamer. All evaluations follow the standard protocol on the AV2 validation set. Experiments are conducted without dual training to neglect confounding influences and isolate the effect of instance-aware context streaming.
Method
Streaming
B=1
B=16
B=32
B=64
B=128
Model Parameters
AV2 Test Set brier-minFDE 6
QCNet [ 54 ]
✗
141 ms
303 ms
565 ms
1092 ms
-
7.7M
1.91
RealMotion [ 36 ]
✓
19 ms
44 ms
0 79 ms
140 ms
273 ms
2.9M
1.89
DeMo [ 50 ]
✓
0 25 ms
35 ms
0 49 ms
00 88 ms
180 ms
5.9M
1.84
SHARP (Ours)
✓
0 21 ms
33 ms
0 35 ms
00 57 ms
105 ms
4.6M
1.83
Appendix
Table 17: Latency analysis for batches of size B when performing single-agent prediction , evaluated on the Argoverse 2 validation set with an NVIDIA RTX 3090 GPU. Larger batch sizes B correspond to more practically-relevant latency estimates, since real-world deployments must process multiple surrounding traffic agents, i.e . B>1 , simultaneously. For QCNet we run out of GPU memory when testing B=128 .
Dataset
RoI
Agents
Lanes
Input Window
Radius
Features
Types
Features
Types
Pl
Length Th
AV1 [ 4 ]
150 m
xy -pos
Vehicle
xy -pos
Standard Lane
10
0.5 s
AV2 [ 44 ]
150 m
xy -pos, xy -vel
Veh./Pedest./Cycl./Others
xy -pos
Veh./Bike/Bus
20
1 s
nuScenes [ 2 ]
100 m
xy -pos
Car/Pedest./Cycl./Other Veh./Motorcycl./Others
xy -pos
Standard/Intersection
20
0.5 s
Appendix
Table 18: Data preprocessing and sampling parameters for loading data from Argoverse 1 (AV1), Argoverse 2 (AV2), and nuScenes. RoI radius denotes the region of interest radius used to sample surrounding agent and map data.
Figure 4: Comparison of motion forecasting processing schemes: standard snapshot-based forecasting, the streaming-based forecasting used by RealMotion [ 36 ] and Demo [ 50 ] (long, overlapping, observation windows) and our proposed approach (compact, subsequent, observation windows).
Figure 5: Details for evaluating related work on the evolving scene setting (main paper Table 1). The first example shows the standard execution on the AV2 benchmark. In the second example, we increase the input context by simply executing another streaming step. In the last example, we test the models with fewer context by evaluating after two streaming steps.
Figure 6: Qualitative single-agent prediction results of our SHARP on scenarios from the Argoverse 2 validation set. We visualize the predictions of our streaming-based method at tp∈{3,4,5} s. The visualizations also show ground truth future , historical agent observations , and surrounding agents . For comparison, the right column shows the predictions of DeMo [ 50 ] at the AV2 standard prediction time step tp =5 s.
Figure 7: Failure cases of our SHARP on scenarios from the Argoverse 2 validation set. We visualize the predictions of our streaming-based method at tp∈{3,4,5} s. The visualizations also show ground truth future , historical agent observations , and surrounding agents . For comparison, the right column shows the predictions of DeMo [ 50 ] at the AV2 standard prediction time step tp =5 s. In the first scenario, a vehicle is waiting at an intersection but will initiate a right turn later – an action that is not anticipated from the current observations. In the second scenario, a vehicle turns into a driveway that is not represented in the map data. In the final scenario, a vehicle stops in the future for a reason that is not captured in the current perception data.