Vehicle reliability: what it is and how to calculate it

Vehicle reliability, a critical term in fleet management, assesses a vehicle's ability to perform its function properly over a specific period.

This maintenance indicator is important for determining the right time for maintenance, minimizing the impact on availability and reducing fleet idle time.

Reliability-centered maintenance (RCM or MCC) is a methodology for measuring and controlling reliability, bringing together good maintenance practices to identify the causes of failures and more effective prevention strategies.

Take a look at the main points:

• What is vehicle reliability?
• How does vehicle reliability work and what is it used for?
• How do you calculate vehicle reliability?
• How can the reliability indicator be improved?

What is vehicle reliability?

Vehicle reliability is an essential indicator in fleet maintenance management. It measures the probability of a vehicle working without failures over a specific period.

For example, if a truck's reliability is 95%, this means that, within the defined period, whether one month or six months, there is a 95% probability that it will work without failures.

Besides transportation, reliability is also a valuable indicator in other areas, such as industry, where the performance of machinery and equipment is checked.

How does vehicle reliability work and what is it used for?

Vehicle reliability is calculated using a formula that assesses, as a percentage, the probability that a vehicle will work properly over the time analyzed. This calculation takes into account the vehicle's Mean Time Between Failures (MTBF) and failure rate.

The main purpose of this indicator is to assist managers with fleet maintenance, enabling more organized and efficient management. This results in various benefits, including:

• Improvement in fleet MTBF

Vehicle reliability helps identify problems more precisely, allowing them to be corrected before they cause serious failures, which increases the mean time between failures.

• Increased fleet maintenance productivity

With reliability, maintenance can be scheduled more strategically, avoiding unplanned interruptions to operations.

• Adoption of better strategies for solving vehicle problems

Through reliability, it is possible to adopt proactive maintenance strategies, meaning that failures are identified and resolved before they significantly affect operations.

How do you calculate the reliability indicator over time?

Vehicle reliability is calculated in 3 steps:

1 – Calculate MTBF

MTBF is a vehicle's Mean Time Between Failures indicator and calculates, in hours, the time between one stoppage and the next for a fleet asset. The formula presented for this indicator is:

MTBF = (hours worked – hours in corrective maintenance) / number of corrective stoppages

2 – Calculate the Failure Rate

The Failure Rate, or FR, represents the frequency of failures considered in the vehicle reliability analysis.

3 – Calculate vehicle reliability

With the results obtained in the previous steps, you can calculate vehicle reliability over time using the formula:

R(t) = e^-λ.t × 100

Where:

R: Reliability

t: Time measured

e: base of natural logarithms

λ: failure rate considered in the calculation

The result expresses the probability of the vehicle operating without failures during the period analyzed. It is therefore worth keeping consistent records of corrective stoppages, hours worked and maintenance so that interpreting the indicator helps guide maintenance decisions.

Watch the video we prepared on how to calculate MTBF:

(video in Portuguese)

How can vehicle reliability be improved?

To improve vehicle reliability, you should follow some important steps:

1. Assess the current reliability indicator

Before starting any improvement, you should know the fleet's current reliability level. This can be obtained through the calculations presented earlier and analyses based on maintenance data and failure history.

2. Adopt good maintenance practices

Implementing good maintenance practices includes carrying out preventive maintenance according to manufacturers' recommendations, as well as using original, high-quality spare parts.

3. Use management tools

Using maintenance management systems can help keep track of fleet performance, schedule preventive maintenance and identify problems at an early stage.

4. Prioritize preventive maintenance

Preventive maintenance is more effective and economical than corrective maintenance. It helps identify and resolve problems before they become serious, increasing vehicle reliability.

5. Keep track of and analyze other maintenance indicators

Establish performance indicators (KPIs) to measure your fleet's maintenance, such as MTBF or vehicle availability. Keep track of these indicators regularly and analyze the results to identify areas that need improvement.

By following these guidelines and implementing the recommended practices, you will be on the right path to improving the reliability of your fleet's vehicles.

Also discover the fleet maintenance management system that makes it easier to manage vehicles and fleet indicators.