> ## Documentation Index
> Fetch the complete documentation index at: https://docs.repdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Traffic Controls (Pacing)

> Spread sample delivery over your field window using No Pacing, Accelerated, or Even pacing.

Traffic Controls limit how quickly respondents enter your survey, spreading data collection across your field dates instead of filling quotas as fast as possible.

## When to use pacing

| Need                                                             | Setting                |
| ---------------------------------------------------------------- | ---------------------- |
| Close fieldwork as fast as possible                              | **No Pacing Required** |
| Fast fill with moderate spread                                   | **Accelerated Pacing** |
| Strict spread — quota not full until \~90% of field time elapsed | **Even Pacing**        |

## How pacing works

Research Desk divides your **Target (N)** across field dates into two-hour increments using:

* **Fieldwork start** — when the source was first set to Live
* **Fieldwork end** — the out-of-field date/time on the project (update during fieldwork if plans change)

When you first go Live, the limit applies to one increment. After each hour, the allowed cumulative volume grows (one increment, then two, then three, and so on). Limits refresh every two hours.

## Formulas

| Setting                | Rule                                                                     |
| ---------------------- | ------------------------------------------------------------------------ |
| **No Pacing Required** | Quota achieved % must not exceed 100% of target                          |
| **Accelerated Pacing** | Quota achieved % must not exceed fieldwork elapsed % × target × **1.75** |
| **Even Pacing**        | Quota achieved % must not exceed fieldwork elapsed % × target × **1.1**  |

Where:

* **Fieldwork elapsed %** = (current time − fieldwork start) ÷ (fieldwork end − fieldwork start)
* **Quota achieved %** = completes achieved ÷ target (for Completes calculation type) or entrants achieved ÷ target (for Survey Starts)

## Example

Source goes Live **Jan 1 at 5:00 PM CT**, out-of-field **Jan 11 at 5:00 PM CT** (10 days). Target N = 1,000.

| Day    | Even distribution | Accelerated max (cumulative)  | Even max (cumulative)                      |
| ------ | ----------------- | ----------------------------- | ------------------------------------------ |
| Day 1  | 100               | 175                           | 110                                        |
| Day 2  | 200               | 350                           | 220                                        |
| Day 5  | 500               | 875                           | 550                                        |
| Day 9  | 900               | —                             | 990 (Even cannot reach 1,000 before Day 9) |
| Day 10 | 1,000             | Can reach 1,000 by late Day 5 | Reaches 1,000 on Day 10                    |

## Setting traffic control

1. Set an accurate **out-of-field date and time** on the project — update it during fieldwork if the timeline changes
2. Select **Traffic Control** when creating a new Internal source or using Quick Launch
3. Respondents enter only while the current pacing limit has not been reached

## Related guides

* [Scheduled Launch](/research-desk/guides/14-scheduled-launch)
* [Source Quota Calculation Types](/research-desk/guides/10-source-quota-calculation-types)
* [Managing Fieldwork](/research-desk/guides/05-managing-fieldwork)