Min radius
min_radius_m
Absolute minimum horizontal curve radius R_min (m)
Scores if within ±3% of the reference value.
Calculates the absolute minimum and desirable minimum horizontal curve radius for road design using R_min = V^2 / (127 * (e_max + f)) per Austroads Guide to Road Design Part 3 Section 7. The desirable radius uses a reduced friction factor (0.7f) for an additional safety margin. Used in road geometric design to ensure vehicle stability and driver comfort on horizontal curves.
with-tool: The model is given an executable Python calculator script.
Standards
One template produces many comparable benchmark tasks while keeping the scoring contract fixed.
01
The reusable contract shown on this page.
02
An archetype and site context are sampled.
03
Inputs may be hidden at harder tiers.
04
The model responds with the declared outputs.
Inputs the model receives, and the outputs it is scored on.
3 inputs
Included directly in every task prompt.
Design speed
design_speed_km_h
Design speed V
Max superelevation pct
max_superelevation_pct
Maximum superelevation rate e_max
Sampled from the scenario and inferable from its description.
Side friction factor
side_friction_factor
Side friction factor f (speed-dependent, from AGRD Table 7.5)
Derived from the archetype scenario. Hidden at hard difficulty.
2 outputs
min_radius_m
Absolute minimum horizontal curve radius R_min (m)
Scores if within ±3% of the reference value.
desirable_min_radius_m
Desirable minimum horizontal curve radius R_desirable (m)
Scores if within ±3% of the reference value.
Each template is sampled at three tiers. Harder tiers may hide inputs, forcing the model to infer them from the scenario description.
All inputs given
All parameters given, low-speed urban or suburban road
All inputs given
All parameters given, any road type and speed environment
Some inputs hidden
Side friction factor hidden — agent must infer f from design speed using AGRD Table 7.5
Hidden inputs
Prompt replacement text
The road is a {{ archetype.description }} ({{ archetype.site_context }}). Determine the appropriate side friction factor from AGRD Table 7.5 for the given design speed.
The exact instruction and parameter contract used to generate this task, pinned to the published library source.
/workspace
Teal lines show Jinja input conditions, not task visibility policy. A line renders only when that input or tool is visible.
1You are a senior civil engineer specializing in road geometry and horizontal alignment design.2 3## Problem4 5Determine the minimum horizontal curve radius and the desirable minimum horizontal curve radius for a road alignment.6 7## Given8 9| Parameter | Value | Unit |10|-----------|-------|------|11| Design speed (V) | {{ design_speed_km_h }} | km/h |12| Maximum superelevation rate (e_max) | {{ max_superelevation_pct }} | % |13{% if side_friction_factor is defined %}14| Side friction factor (f) | {{ side_friction_factor }} | - |15{% endif %}16{% if archetype_description is defined %}17 18### Site Conditions19 20{{ archetype_description }}21{% endif %}22 23{% if tool_available %}24## Available Tool25 26A minimum curve radius calculation tool is available at `/workspace/{{ meta.name }}_calc.py`. Run it with:27 28```bash29python3 /workspace/{{ meta.name }}_calc.py --help30```31 32You may use this tool to verify your calculations or compute values directly.33{% endif %}34 35## Required36 37Calculate the following:38 391. Absolute minimum horizontal curve radius R_min (m)402. Desirable minimum horizontal curve radius R_desirable (m)41 42## Applicable Standards43 44- Austroads Guide to Road Design Part 3 (AGRD Part 3 §7)45 46## Constraints47 48- No internet access is available. Work from engineering knowledge and the provided tool.49- Use the point-mass equilibrium equation for minimum curve radius:50 - R_min = V² / (127 × (e_max + f))51 - where V is design speed in km/h, e_max is the maximum superelevation rate as a decimal (e.g. 0.06 for 6%), and f is the side friction factor52- For the desirable minimum radius, use a reduced friction factor of 0.7 × f:53 - R_desirable = V² / (127 × (e_max + 0.7 × f))54{% if side_friction_factor is not defined %}55- Side friction factors from AGRD Table 7.5 (speed → f):56 40 km/h → 0.35, 50 → 0.33, 60 → 0.30, 70 → 0.26, 80 → 0.22, 90 → 0.19, 100 → 0.16, 110 → 0.13, 120 → 0.11, 130 → 0.0957{% endif %}58 59## Output Format60 61Show your step-by-step working in Markdown. At the end of your solution, include a JSON block with your final answers in exactly this format:62 63```json64{65 "min_radius_m": <numeric_value>,66 "desirable_min_radius_m": <numeric_value>67}68```69 70Write your complete solution to `/workspace/output.md`.71 Each generated task is drawn from one of these realistic scenario bands.
Site contexts ground each scenario in a real locale the model can use to infer hidden values.
urban_local
Low-speed urban local road with frequent intersections and pedestrian activity
suburban_arterial
Suburban arterial road with moderate traffic and signalised intersections
rural_highway
Rural two-lane highway through open terrain with higher operating speeds
motorway
High-speed divided motorway with grade-separated interchanges
sydney-parramatta-road-suburban-arterial-preview — hard difficulty, some inputs hidden.
Suburban arterial road with moderate traffic and signalised intersections. sydney-parramatta-road. Required outputs: min_radius_m, desirable_min_radius_m
Scenario context and visible inputs.
Executable tool: min-curve-radius_calc.py
Inputs withheld at this difficulty.
Side friction factor
side_friction_factor
Stand-in text in the prompt
The road is a {{ archetype.description }} ({{ archetype.site_context }}). Determine the appropriate side friction factor from AGRD Table 7.5 for the given design speed.
The scored JSON answer schema.
{
"min_radius_m": <number>,
"desirable_min_radius_m": <number>
}