Traffic and Road Data
The Traffic and Road Data page supplies road user cost (RUC) inputs for the social pillar of LCCA. In INDIA mode, the app computes delay, accident, and operating costs from vehicle counts, road geometry, traffic flow, and Wholesale Price Index (WPI) adjustment factors. In GLOBAL mode, a single aggregated daily road user cost replaces the detailed India model.
E.1 Calculation Mode
Click Traffic and Road Data in the left navigation menu. The first control is Calculation Mode.
| Mode | When available | Panel shown |
|---|---|---|
| INDIA | Project country is India | Vehicle table, alternate route, road parameters, peak hours, WPI section |
| GLOBAL | Any project; forced when country is not India | Road User Cost per Day only |
E.1.1 Country-dependent behaviour
On page display, the app reads Project Country from General Information:
- India: Calculation Mode is enabled. The user may switch between INDIA and GLOBAL.
- Not India: Calculation Mode is locked to GLOBAL. The INDIA panel is hidden.
The active mode is stored in the project as mode (INDIA or GLOBAL).
[TODO - screenshot not yet available: documentation_images/partE/01_calculation_mode_india.png]
[TODO - screenshot not yet available: documentation_images/partE/02_calculation_mode_global.png]
E.1.2 GLOBAL mode validation
| Condition | Result |
|---|---|
| Road User Cost per Day ≤ 0 | Warning: Road User Cost per Day is 0 - road user cost will not be included - orange border |
No other fields appear in GLOBAL mode.
E.2 Vehicle Traffic Data
Available in INDIA mode only. The Vehicle Traffic Data table lists eight fixed vehicle categories.
E.2.1 Vehicle categories and columns
| Vehicle Type | Vehicles / Day | Accident % | PWR |
|---|---|---|---|
| Small Car | Editable (0–9,999,999) | Editable (0.00–100.00) | - |
| Big Car | Editable | Editable | - |
| Two Wheeler | Editable | Editable | - |
| Ordinary Buses | Editable | Editable | - |
| Deluxe Buses | Editable | Editable | - |
| LCV | Editable | Editable | - |
| HCV | Editable | Editable | Editable (0.00–999.90); default 7.22 |
| MCV | Editable | Editable | Editable (0.00–999.90); default 8.00 |
| Column | Meaning |
|---|---|
| Vehicles / Day | Average daily traffic (ADT) for that vehicle class on the bridge approach road. |
| Accident % | Share of total accident involvement attributed to that vehicle class. All classes must sum to 100% when any traffic is entered (see E.2.3). |
| PWR | Power-to-weight ratio - used for HCV and MCV only. Shown as - for other classes. |
E.2.2 Force free-flow conditions off-peak
Checkbox below the vehicle table: Force free-flow conditions off-peak.
- Default: checked
- When checked, off-peak periods are modelled as free-flow for operating-cost calculations
- Stored as
force_free_flow_off_peak
[TODO - screenshot not yet available: documentation_images/partE/03_vehicle_traffic_table.png]
E.2.3 Validation rules (vehicle table)
Validation applies when the sum of Vehicles / Day across all classes is greater than zero.
| Condition | Result |
|---|---|
| Sum of Vehicles / Day = 0 | Warning: No vehicle traffic data - all vehicles per day are 0 - road user cost from detailed traffic is skipped; vehicle-table checks below are not run |
| Sum of Accident % ≠ 100% (tolerance ±0.1) | Error: Vehicle accident percentages must sum to 100% - currently X.X% - red border on table |
| HCV or MCV has Vehicles / Day > 0 and PWR ≤ 0 | Error: PWR must be > 0 for HCV when vehicles per day > 0 (or MCV) |
When all Vehicles / Day values are zero, the user effectively opts out of India-model road user costs; only the WPI zero-value check still runs (see E.7).
E.3 Alternate Road Configuration
Section Alternate Road Configuration defines the detour route used during construction and maintenance closures.
E.3.1 Fields
| Field | Required | Description |
|---|---|---|
| Alternate Road Carriageway | Yes | Lane configuration of the alternate route. First option: - Select - (invalid for calculation). |
| Carriageway Width | Yes | Width of the alternate carriageway in metres. |
| Hourly Capacity | Yes | Design hourly capacity of the alternate route (veh/hr). |
E.3.2 Lane-type options and auto-fill
Selecting a lane type auto-fills Carriageway Width and Hourly Capacity from built-in IRC-style defaults:
| Alternate Road Carriageway | Carriageway Width (m) | Hourly Capacity (veh/hr) |
|---|---|---|
| Single Lane | 3.75 (locked) | 435 |
| Intermediate Lane | 5.50 (locked) | 1,158 |
| Two Lane (Two Way) | 7.00 (locked) | 2,400 |
| Two Lane (One Way) | 7.00 (locked) | 2,700 |
| Three Lane (One Way) | 10.50 (locked) | 4,200 |
| Four Lane (Two Way) | 7.00 (locked) | 5,400 |
| Six Lane (Two Way) | 10.50 (locked) | 8,400 |
| Eight Lane (Two Way) | 14.00 (locked) | 13,600 |
| 4 Lane Expressway (Two Way) | User entry (enabled) | 5,000 |
| 6 Lane Expressway (Two Way) | User entry (enabled) | 7,500 |
| 8 Lane Expressway (Two Way) | User entry (enabled) | 9,200 |
- - Select -: Carriageway Width and Hourly Capacity reset to 0; width field disabled.
- Fixed-width lane types: Carriageway Width is auto-filled and disabled.
- Expressway types: width is not preset (
Nonein data); Carriageway Width is enabled for manual entry.
The selected display name is stored internally as an IRC code (e.g. 2L for Two Lane (Two Way)).
[TODO - screenshot not yet available: documentation_images/partE/04_alternate_road_autofill.png]
E.3.3 Validation rules
| Condition | Result |
|---|---|
| Alternate Road Carriageway = - Select - | Error: Alternate Road Carriageway must be selected |
| Carriageway Width = 0 | Error: Carriageway Width cannot be 0 |
| Hourly Capacity = 0 (when total ADT > 0) | Error: Hourly Capacity cannot be 0 |
Hourly Capacity and carriageway checks are skipped when all Vehicles / Day values are zero.
E.4 Accident Severity Distribution
Section Accident Severity Distribution splits accidents by injury outcome. Three percentage fields:
| Field | Range | Description |
|---|---|---|
| Minor Injury | 0.00–100.00 (%) | Percentage of accidents resulting in minor injury |
| Major Injury | 0.00–100.00 (%) | Percentage of accidents resulting in major injury |
| Fatal Accident | 0.00–100.00 (%) | Percentage of accidents resulting in fatal injury |
E.4.1 Auto-balancing behaviour
The three fields are linked so the total remains 100%:
- Editing Minor Injury: Fatal Accident adjusts to
100 − Minor − Majorif Major ≤ remaining; otherwise Major is capped and Fatal set to 0. - Editing Major Injury: if Minor + Major > 100, Major is capped; Fatal Accident =
100 − Minor − Major. - Editing Fatal Accident: if Minor + Fatal > 100, Fatal is capped; Major Injury =
100 − Minor − Fatal.
E.4.2 Validation rules
When total ADT > 0:
| Condition | Result |
|---|---|
| Minor + Major + Fatal ≠ 100% (tolerance 1×10⁻⁴) | Error: Accident severity must sum to 100% - currently X.X% |
[TODO - screenshot not yet available: documentation_images/partE/05_accident_severity.png]
E.5 Road Parameters
Section Road Parameters describes operating conditions on the alternate/detour route and work-zone exposure.
E.5.1 Field reference
| Field | Required | Range | Description |
|---|---|---|---|
| Road Roughness | No | 2,000–100,000 (mm/km) | Surface smoothness; lower values indicate smoother ride quality. |
| Road Rise | Yes | 0.000–9,999.000 (m/km) | Upward gradient of the alternate road. |
| Road Fall | Yes | 0.000–9,999.000 (m/km) | Downward gradient of the alternate road. |
| Additional Reroute Distance | No | 0.000–9,999.000 (km) | Extra distance travelled due to rerouting during construction or maintenance. |
| Additional Travel Time | No | 0.000–9,999.000 (min) | Extra travel time from rerouting. |
| Crash Rate | Yes | 0.00–999,999.00 (acc / M km) | Accidents per million vehicle-kilometres of road length per day. |
| Work Zone Multiplier | Yes | 0.0000–1.0000 | Multiplier for accident risk or delays under work-zone conditions. Default: 1. |
E.5.2 Role in LCCA
| Parameter | Role in the analysis |
|---|---|
| Road Roughness | Affects vehicle operating costs (fuel, tyre wear, maintenance) on the detour route. |
| Road Rise / Road Fall | Gradient affects fuel consumption and travel speed for heavy and light vehicles. |
| Additional Reroute Distance | Length of detour; scales delay and operating costs during closures. Also referenced from Carbon Emission → Traffic Diversion. |
| Additional Travel Time | Fixed extra time per trip on the detour, independent of distance-based delay. |
| Crash Rate | Baseline accident frequency on the route; combined with vehicle mix and severity split for accident costs. |
| Work Zone Multiplier | Scales accident exposure near the construction/maintenance zone. Value 0 disables work-zone accident scaling (warning shown). |
E.5.3 Validation warnings
| Field | Warning condition | Message |
|---|---|---|
| Road Rise | < 0.01 or > 9,999 | Road Rise is 0 or unusually high - please verify the value |
| Road Fall | < 0.01 or > 9,999 | Road Fall is 0 or unusually high - please verify the value |
| Additional Reroute Distance | < 0.01 or > 1,000 | Additional Reroute Distance is 0 or unusually high - please verify the value |
| Additional Travel Time | < 0.01 or > 1,000 | Additional Travel Time is 0 or unusually high - please verify the value |
| Crash Rate | < 0.01 or > 10,000 | Crash Rate is 0 or unusually high - please verify the value |
| Work Zone Multiplier | < 0.001 | Work Zone Multiplier is 0 - work zone accident scaling will be disabled |
Road Rise, Road Fall, and Crash Rate are required. A value still at the spin-box minimum (0) is treated as unset for required fields with default 0.
[TODO - screenshot not yet available: documentation_images/partE/06_road_parameters.png]
E.6 Traffic Flow and Peak Hour Distribution
E.6.1 Number of Peak Hours
| Field | Required | Range | Description |
|---|---|---|---|
| Number of Peak Hours | Yes | 0–24 | Count of peak traffic hours modelled per day. |
Changing Number of Peak Hours rebuilds the Peak Hour Distribution table with that many editable peak rows plus one fixed summary row.
| Warning condition | Message |
|---|---|
| < 1 or > 24 | Number of Peak Hours must be between 1 and 24 |
Default proportion for each new peak row: 4.00 %.
E.6.2 Peak Hour Distribution table
| Row | Editable | Description |
|---|---|---|
| Peak Hour 1 … Peak Hour N | Yes (0.00–100.00 %) | Share of daily traffic occurring in that peak hour. |
| Other Hours (Average) | No (computed) | Average proportion for the remaining 24 − N hours. |
Other Hours (Average) is calculated as:
Other Hours (%) = (100 − sum of peak proportions) / (24 − N)
When a peak proportion changes, each peak spin box’s maximum is capped so the peak total cannot exceed 100%.
E.6.3 Validation rules (peak hours)
Applied when total ADT > 0 and Number of Peak Hours > 0:
| Condition | Result |
|---|---|
| Any peak hour proportion = 0 | Error: Peak hour proportion cannot be 0: Peak Hour X (lists affected hours) |
| Sum of peak proportions > 100% | Error: Peak hour proportions sum to X.X% - must be ≤ 100% |
Peak values are stored as fractions (e.g. 10% → 0.1 under peak_hour_1, peak_hour_2, …).
[TODO - screenshot not yet available: documentation_images/partE/06_peak_hour_distribution.png]
E.7 WPI Adjustment Factors
INDIA mode only. The WPI Adjustment Factors section applies Wholesale Price Index–based ratios to road user cost components by vehicle type.
E.7.1 Profile selector
| Control | Behaviour |
|---|---|
| WPI Profile: dropdown | Lists database profiles (bold) and custom profiles (prefixed with ★). |
| Integrity badge | ✅ verified, ⚠ hash mismatch, ❓ no hash - tooltip describes state and DB vs Custom. |
| + New | Creates a blank custom profile (name, year, optional remark dialog). |
| ✎ Save As | Saves current table values as a new custom profile. |
| 🗑 Delete | Deletes the selected custom profile only (DB profiles cannot be deleted). |
| ⬆ Save to My Library | Saves current profile + table data to the global user WPI library (user.db). |
| ⬇ Import from Library | Imports a library profile as a new custom profile in this project. |
On load, if any database profile fails integrity verification, a red warning lists unlisted profile names.
E.7.2 WPI table structure
The table has 16 cost columns under six group headings:
| Group | Columns |
|---|---|
| Fuel Cost | Petrol, Diesel, Engine Oil, Other Oil, Grease |
| Vehicle Cost | Prop. Damage, Tyre Cost, Spare Parts, Fixed Depr. |
| Commodity | Hold. Cost |
| Pass. & Crew | Passenger, Crew |
| Medical Cost | Fatal, Major, Minor |
| VOT Cost | VOT Cost |
Rows:
- Group header row (Fuel Cost, Vehicle Cost, …)
- Column label row
- Common to All checkbox row
- One data row per vehicle: Small Car, Big Car, Two Wheeler, Ordinary Bus, Deluxe Bus, LCV, HCV, MCV
E.7.3 Editable vs read-only behaviour
| Profile type | Table cells | Common to All checkboxes |
|---|---|---|
| Database profile | Read-only | Disabled (vehicle-specific columns only) |
| Custom profile | Editable per rules below | Enabled on vehicle-specific columns |
Common to All (vehicle-dimension columns only):
- Checked (default when all vehicle values in a column are equal): one value applies to all vehicles; only the first vehicle row is editable; other rows mirror the first and appear dimmed.
- Unchecked: each vehicle row is independently editable.
- Non-vehicle columns (Petrol, Diesel, Passenger, Crew, Fatal, Major, Minor): checkbox is disabled with tooltip This factor is not vehicle-specific - always common to all.
On save, the app stores a snapshot with base (2019 profile), selected (current table), and ratio (selected ÷ base element-wise).
E.7.4 Validation rules (WPI)
WPI validation runs regardless of vehicle ADT.
| Condition | Result |
|---|---|
| Any checked Common to All column has first-row value = 0 | Error: WPI value cannot be zero: <Group / Label> |
| Any unchecked column has any vehicle row = 0 | Error: WPI value cannot be zero: <Group / Label> (<Vehicle>) |
[TODO - screenshot not yet available: documentation_images/partE/07_wpi_table.png]
E.8 Remarks and Page Validation
Shared by both calculation modes.
E.8.1 Remarks / Notes
Rich-text Remarks / Notes editor at the bottom of the page. Content is stored as HTML in the project and included in reporting when populated.
E.8.2 Clear All
Click Clear All. Confirmation is required.
On confirmation:
- Vehicle table, peak table, remarks, and all form fields reset to defaults
- Alternate Road Carriageway returns to - Select -
- WPI selector resets to the first listed database profile
- Validation result label is hidden
E.8.3 Validate this page
Click Validate this page to run the same checks as Calculate for this page only. Results appear below the buttons:
| Outcome | Display |
|---|---|
| No errors or warnings | Green: ✔ All checks passed |
| Errors | Red ✖ lines with message text |
| Warnings | Orange ⚠ lines with message text |
[TODO - screenshot not yet available: documentation_images/partE/08_validate_page.png]
E.9 Example values - Sone River Road Bridge
INDIA mode example for a 2-lane state-highway bridge (Bihar). Align Alternate Road Carriageway with the two-lane detour typical for this project.
Calculation Mode: INDIA
Vehicle Traffic Data
| Vehicle Type | Vehicles / Day | Accident % | PWR |
|---|---|---|---|
| Small Car | 2,200 | 18.00 | - |
| Big Car | 650 | 10.00 | - |
| Two Wheeler | 2,800 | 68.00 | - |
| Ordinary Buses | 15 | 1.00 | - |
| Deluxe Buses | 80 | 1.00 | - |
| LCV | 120 | 1.00 | - |
| HCV | 25 | 0.50 | 7.22 |
| MCV | 10 | 0.50 | 8.00 |
Force free-flow conditions off-peak: checked
Alternate Road Configuration
| Field | Value |
|---|---|
| Alternate Road Carriageway | Two Lane (Two Way) |
| Carriageway Width | 7.00 m (auto-filled) |
| Hourly Capacity | 2,400 veh/hr (auto-filled) |
Accident Severity Distribution: Minor Injury 30.00 %, Major Injury 55.00 %, Fatal Accident 15.00 %
Road Parameters
| Field | Value |
|---|---|
| Road Roughness | 3,500 mm/km |
| Road Rise | 2.000 m/km |
| Road Fall | 1.500 m/km |
| Additional Reroute Distance | 3.500 km |
| Additional Travel Time | 8.000 min |
| Crash Rate | 120.00 acc / M km |
| Work Zone Multiplier | 1.0000 |
Traffic Flow
| Field | Value |
|---|---|
| Number of Peak Hours | 2 |
| Peak Hour 1 | 10.00 % |
| Peak Hour 2 | 10.00 % |
| Other Hours (Average) | 3.64 % (computed) |
WPI: Select the latest available database profile for the analysis year (e.g. 2025). Custom edits are optional.
For a non-India project or a screening study, switch to GLOBAL and enter Road User Cost per Day directly.
E - Screenshot checklist
| Checklist Item | File |
|---|---|
| Calculation Mode - INDIA panel (annotated) | documentation_images/partE/01_calculation_mode_india.png |
| Calculation Mode - GLOBAL panel (annotated) | documentation_images/partE/02_calculation_mode_global.png |
| Vehicle Traffic Data table (annotated) | documentation_images/partE/03_vehicle_traffic_table.png |
| Alternate Road Configuration auto-fill (annotated) | documentation_images/partE/04_alternate_road_autofill.png |
| Accident Severity Distribution (annotated) | documentation_images/partE/05_accident_severity.png |
| Peak Hour Distribution (annotated) | documentation_images/partE/06_peak_hour_distribution.png |
| WPI Adjustment Factors table (annotated) | documentation_images/partE/07_wpi_table.png |
| Validate this page (annotated) | documentation_images/partE/08_validate_page.png |