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Pros and Cons of Automatic Engine Start/Stop Solutions

Pros and Cons of Automatic Engine Start/Stop Solutions

The idea of ‘Idle Reduction’ is broad, complicated, and includes many technologies and solutions, including automatic start/stop engine solutions, that might work well together or conflict with each other. Each solution promises some type of benefit, but there is never a silver bullet that can be a perfect idle reduction solution.

The North American Council for Freight Efficiency (NACFE) put together an excellent review and report of all the idle reduction solutions on the market today, listing the advantages and disadvantages of each solution from a neutral position and looking at just the facts and research. If you aren’t familiar with NACFE, it is a great organization that provides in-depth and quality research to help fleets run more efficiently.

Automatic start/stop technology is becoming increasingly popular in various industries as it offers significant fuel savings and reduces emissions during idling.

The following is a copy of the NACFE’s report on automatic start/stop solutions. You can read the full NACFE Confidence Report by clicking here.

Overview of Automatic Engine Start/Stop Solutions

Functionality

Once the engine is running, the vehicle’s HVAC systems will warm or cool the sleeper just as they would when the truck is driving down the road. Essentially, the vehicle is still idling, keeping the engine warm and the batteries charged, but it is able to do so much more intelligently/efficiently, and automatically.

These systems can be used in very cold climates, for instance while a truck is in storage for a weekend or other down time, and offer very beneficial results, ensuring the vehicle will start when it is time to go back into freight-hauling operation. Automatic engine start/stop systems perform the work of both a block heater and battery charger without the need for the truck to be connected to outside power.

Types of Automatic Engine Start/Stop Systems

There are two different types of automatic engine start/stop systems, the most common being one that has a goal of maintaining a cab’s interior temperature when the vehicle is occupied. These may also assist with keeping the engine warm and the batteries charged.

The newer and less common type of automatic engine start/stop system focuses solely on maintaining the batteries’ state of charge. Given the growth in use of battery HVACs, combined with the new HOS restarts that last far longer than the 8 to 12 hours a battery HVAC can operate on one charge, this type of automatic engine start/stop system will probably grow in popularity, as they serve to recharge the battery HVAC system as it has drawn itself down. These will therefore enable battery HVACs to idle for longer than a single 8-10 hour window, allowing a driver to enjoy air conditioning continuously during an HOS restart. This type of automatic engine start/stop system is programmed to recognize the specific type of batteries being used by the battery HVAC system, and monitor their voltage, current draw, and temperature to provide optimal recharging patterns by comparing the inputs they receive to electronically stored battery-life models. It will typically require about 45 minutes of engine operation (which the automatic engine start/stop system will control) to fully recharge a battery HVAC system for an additional 8-10 hours of operation.

Advantages of Automatic Engine Start/Stop Systems

The most obvious benefit of all automatic start/stop systems is that they add few components and little weight to the vehicle. Since they are controlling the main engine, they do not require additional HVAC components, batteries, or engines to accomplish their tasks.

If a vehicle is purchased with a California Air Resources Board (ARB) “Clean Idle” engine, it will have a serial-numbered holographic sticker on the driver’s side of the hood or driver’s door. Such stickers allow automatic engine start/stop systems to be used without violating any idling regulations, provided that the vehicle wasn’t also purchased with the tamperproof five-minute timer, which does not allow any idling at all beyond that time limit.

Clean idle engines offer an integrated and clean solution that utilizes a few extra sensors to provide all of the desired HVAC and hotel load benefits while the vehicle is not moving. It may also be the solution most preferred by fleet maintenance teams, given its simplicity/commonality of diagnostics, service and parts.

Disadvantages of Automatic Engine Start/Stop Systems

The initial automatic engine start/stop systems that came out about two decades ago were not well-liked by truck drivers. Whenever those systems started and stopped the main engine, the noise and vibration could wake a sleeping driver. Some improvements have minimized this problem on newer systems, such as using the engine brake to create a more rapid and smooth engine shut-off than the cab rocking and engine sputtering that occurs during a normal shutoff.

Another drawback of these systems is that they do require idling the main engine, creating additional hours of wear on the main engine and loading of the DPF exhaust system.

Finally, it is not completely clear how various idle laws relate to some of the operational modes available with these systems. If the automatic engine start/stop system is charging the batteries or allowing a regeneration of the DPF system, it should be permissible to allow engine operation longer than the typical five minute maximum, similar to the rules which govern aspects of the electronic engine idle parameters technology class, and are detailed in that section.

Recommendations and Best Practices

If your fleet is dissatisfied with the length of operation of your battery HVAC system, a battery monitoring and charging system, such as that offered by automatic engine start/stop systems, could be a desirable investment to extend operation.

For fleets that are challenged from a support aspect to keep diesel APUs systems in operation, the combination of a Clean Idle engine and an automated engine start/stop system could reduce that challenge.

Again, the information in this post is from NACFE’s report on automatic engine start/stop solutions. You can read the full NACFE Confidence Report by clicking here. Feel free to visit our website or contact us directly at 913-744-4353 to see if Idle Smart can help you.

Interested in reducing the idle time of your fleet? Let’s talk to see if we’re a good fit for your fleet.

Recent Posts

4 Winter Trucking Myths Costing Your Fleet Money

You don't have to accept the costs that winter trucking...

The Challenges of the Cold

Winter trucking always delivers two things to heavy-duty fleets: blistering cold weather and rising operational costs. For too long, the industry has simply accepted the financial hit of no-starts, excessive idling, and maintenance emergencies as an unavoidable reality. But smart fleet technology has changed the game. It’s time to retire the outdated belief that cold weather must equal chaos for your budget and maintenance team.

Here are four persistent problems that fleets have come to accept as part of winter, and the modern framework for overcoming them to protect your assets and profitability.

Myth #1: “Idling all night is the only way to stay warm.”

This is the classic, costly trade-off. For decades, the only reliable way for drivers to guarantee a warm cab for rest and a running engine in the morning was to idle all night. The assumption is that consistent cabin comfort requires consistent engine runtime.

The modern reality is that excessive idling is a massive profit killer. Unnecessary runtime burns through fuel, leading to thousands of dollars in wasted money a year, and strains the engine, which drives up maintenance frequency.

The smarter approach is automated, efficient engine management. Contemporary systems can monitor the cabin temperature and run short, precise engine cycles only when necessary to maintain the driver’s pre-set comfort settings. This cuts the fuel bill while providing uninterrupted rest and consistent climate control.

Myth #2: “My factory idle management system has me covered.”

Factory-installed idle management systems are an attractive option because they’re built-in. However, the core flaw is that they are designed for the individual truck, not for the strategic control required by a whole fleet.

Accepting a factory system means accepting a solution built for basic operation, not for efficiency at scale.

Factory-Installed Idle Management SystemsFleet-Focused Idle Management Systems
Limited Control: They offer a narrow set of factory-preset settings with poor adjustability. They also require seasonal in-shop adjustments. Deep Customization: A modern, fleet-focused system offers a wide array of adjustable parameters for precise optimization that can be adjusted remotely through an online portal.
Driver Dependent: Most require manual driver activation that takes several steps and are easily overridden or accidentally disengaged. Full Automation: The best solutions take tasks off your team’s plate instead of adding to it. Systems that automatically activate regardless of whether the key is out/off help your drivers efficiently cut idle costs while still keeping them comfortable without asking them to do additional work. 
No Fleet Visibility: They lack the in-depth data needed to understand why drivers are idling.Actionable Idle Data: Centralized software gives you real-time visibility into idle behavior and asset utilization to help you coach drivers. 

Myth #3: “A no-start is just part of winter.”

Many fleets accept that battery drain and cold starts are unavoidable, even building roadside assistance into winter budgets. This mindset is expensive, leading to lost revenue from downtime and high-stress emergency calls. Not to mention, increased turnover from stressed drivers.

The truth is that you can reliably and automatically prevent no-starts. This is achieved by moving from simple voltage awareness to proactive, predictable defense.

  • Battery and eAPU Protection: The optimal system proactively monitors battery voltage and automatically starts the engine to recharge the batteries before they drop too low. This feature is critical for eAPUs, as it maintains battery charge to prevent shutdowns that force drivers to manually restart the engine.
  • Cold Start and Fuel Gelling Defense: This protection is paired with technology that automatically monitors engine coolant temperature and starts the engine when needed. This proactively prevents cold start failures and eliminates the risk of fuel gelling.

This combination ensures every truck is ready to roll when the key is turned, eliminating unplanned expenses and guaranteeing uptime.

Myth #4: “Pre-trip inspections are enough to catch winter problems.”

While pre-trip inspections are a vital safety and compliance measure, they only provide a health snapshot at a single point in time. They often miss subtle, underlying engine or emissions issues that are exacerbated by cold weather and are silently progressing toward an emergency.

Predictive Maintenance technology analyzes engine data constantly, filtering out the noise of non-critical fault codes to flag the most critical issues. This capability identifies high-priority maintenance alerts, like a DPF Plugging issue, DEF Dosing Unit Fault, or Low Coolant Level, before they cause an emergency derate or an expensive roadside breakdown. Predictive Insights brings a powerful magnet to the haystack of your fleet’s endless pile of fault codes. 

Adding Predictive Maintenance to your maintenance strategy allows your team to schedule repairs during planned downtime, creating a more predictable budget and eliminating the massive cost and chaos of roadside breakdowns. 

The Smarter Way to Conquer Winter Trucking

You don’t have to accept the costs that winter weather has thrown at you. You can make your budget more predictable and your assets more reliable with Idle Smart.

Our maintenance-free system is designed for fleets, driving true efficiency and a fast ROI that delivers:

  • Guaranteed Uptime through reliable no-start and cold start prevention.
  • Massive Fuel Savings from automated, hyper-efficient engine cycling.
  • Predictive Maintenance Insights to streamline your maintenance workflows and keep your operations running smoothly.
  • Improved Driver Comfort without maintenance, seasonal adjustments, excess weight, or a steep price tag.

Want to see how Idle Smart puts all of this to work for your fleet?

Talk to an Expert Today

Your Quick Idle Smart Coaching Guide

The Idle Smart Driver Coaching and Engagement Guide is designed...

Getting the Most Out of Your Idle Smart Systems

The Idle Smart system is designed for maximum efficiency, but even the best technology needs clear communication to work perfectly. For maintenance leaders and operations executives, maximizing the value of your investment is critical, but the biggest roadblock to realizing your full ROI is often the same: driver resistance.

When a driver raises an objection—”The truck keeps starting at night!” or “I feel out of control!”—it’s not just a complaint; it’s an opportunity. It’s a chance to stop a bad habit, start a productive conversation, and reframe the system as a tool for their personal safety and comfort.

The fleets with the highest adoption rates treat these moments not as technical issues, but as coaching opportunities. 

We created the Idle Smart Coaching and Engagement Guide to help you and your drivers get the most out of your Idle Smart investment; this blog is a sneak peek into some of the tips and tricks included in the guide. 

The Coaching Foundation: Protection, Not Policing

The most successful conversations lead with a driver-focused benefit. Frame every feature around protection, comfort, and uptime that keeps them on the road and earning.

As Sara Young, Idle Smart’s VP of Customer Success, emphasizes;

“The best-in-class fleets we work with introduce Idle Smart to their drivers before it’s even installed. They position it around driver protection and comfort, minimizing jumpstarts, keeping electronics powered all night, and maintaining a safe, comfortable cab temperature. That conversation up front makes all the difference in adoption.”

Your first step? Always start with a simple question to make the driver feel heard: “What happened?” or “What did you see on the screen?” Not only is this great for building trust, but it also helps give you context so you can provide better coaching. 

Idle Smart Coaching: Reframe The Script

This quick-reference guide, adapted from our complete coaching manual, gives your leaders the script they need to turn confusion into confidence.

Driver ObjectionYour Reframe & Coaching PointKey Benefit to Driver
“The truck keeps starting at night and wakes me up.”“Idle Smart only starts when it needs to—whether that’s to keep the cab comfortable, protect your batteries, or prevent a cold start. The short cycles save fuel compared to idling all night and make sure the truck is ready to go when you wake up.”Guaranteed Uptime and protection for sensitive equipment like CPAP machines.
“I don’t like not being in control of the engine.”“You are still in control—you have the manual kill switch for special cases. But by leaving Idle Smart on, it takes the worry off your plate and makes sure the truck is always ready when you are.”Less Stress and Worry about no-starts or dead batteries.
“The cab isn’t staying comfortable in the heat/cold.”“Idle Smart manages when the engine runs, not the vent temps. Is your HVAC set to heat or cool with the fan up? Closing your bunk curtain helps the cab stay steady all night.”Consistent Comfort for uninterrupted rest.

Leveraging Your Customer Success Team

Coaching is one piece, but you don’t have to carry the load alone.

We understand that even with the best internal training, issues can escalate. That’s why our dedicated Customer Success Managers (CSMs) are your partners in optimizing adoption and ensuring your ROI.

  • Ongoing Support: Your CSM can provide guidance on establishing parameters, integrating the system into existing workflows, and implementing incentive programs that actually motivate your drivers.
  • Deep Dive Diagnostics: If a driver reports a persistent issue that your shop can’t resolve, like repeated unexpected shutdowns or a system that won’t connect, your CSM can help your maintenance team quickly diagnose and resolve system-specific issues or VIN/activation problems.

Reinforcing good habits with Idle Smart isn’t a one-and-done deal. It requires clear communication, consistent management, and the right resources to support your drivers.

Read the Coaching and Engagement Guide for more details about reframing conversations and coaching guidance, plus get incentive ideas, get inspiration from customers, and our escalation protocol. 

Download the Free Idle Smart Coaching Guide

ATRI Releases 2025 Critical Issues Report: Is Your Fleet Prepared? Take the Self-Assessment

ATRI's 2025 Critical Issues report shows record costs demanding action....

ATRI Releases 2025 Critical Issues Report 

The American Transportation Research Institute (ATRI) released its annual Critical Issues Report, and the verdict for 2025 is stark. The Economy is the top concern for the third year in a row, confirming that financial stability is the industry’s greatest threat. With non-fuel operational costs documenting a record high of $1.779 per mile and the truckload sector averaging a devastating negative profit margin of -2.3% in 2024, the margin for error has disappeared. This environment demands that your fleet identify and control costs wherever possible.

This year’s landscape signals an industry increasingly focused on managing complexity: from new regulatory compliance burdens to integrating emerging technologies and ensuring a trained, proficient workforce.

Do you think your fleet is handling the complexity of these top concerns well?

By asking tough questions about your day-to-day operations, this self-assessment helps you determine how ready your fleet really is. Plus, it helps you pinpoint hidden costs so your fleet can take meaningful steps toward achieving a significantly lower Total Cost of Ownership (TCO).

The 9-Question Self-Assessment

1. How much does your fleet spend annually on roadside assistance calls due to dead batteries or cold-start failures?

Unplanned service calls are an absolute loss; pure, non-recoverable expense. As the Economy is the number one issue for the third year in a row, you can’t afford this unnecessary added expense. Breakdowns consume driver and staff resources, incur towing fees, and directly chip away at already strained profit margins.

Ask yourself:

  • What’s the total cost of towing, shop time, and labor for a single no-start event?
  • Do you have enough breakdowns that you created a budget line item just to cover roadside assistance?
  • What else could we reallocate that money for if we could stop having frequent, predictable breakdowns?

While there will always be occasional unpredictable events, there’s no reason your team should be dealing with dead batteries daily. Your drivers and technicians deserve equipment that is reliable, so drivers keep wheels turning and earning for your fleet while technicians can stay focused on their most time-sensitive, high-impact work. Eliminating no-starts from easily preventable battery drain or fuel gelling is a direct path to lowering TCO, and it might be easier than you think.

GRADE YOURSELF: PASS/FAIL

2. How much maintenance time and cost do your current solutions require that must be staffed and tracked?

Overall operational costs, excluding fuel, rose by 3.6% in 2024, continuing the upward pressure on non-fuel expenses. Routine APU servicing (recommended every 600-1000 hours) or seasonal in-shop adjustments for auto-starts contribute directly to those rising costs. This overhead pulls your precious technician time away from higher-value repairs. 

Ask yourself:

  • How much time do we track and staff just for APU oil changes, belt replacements, and cleaning HVAC systems?
  • How much could you save if even one of your key systems didn’t require maintenance (all updates can be made automatically without ever pulling a truck off the road)? 
  • Do we spend more time and money maintaining our tech (like APUs) than they actually save?

GRADE YOURSELF: Pass/Fail

3. Do you know why an engine is running, or only that it ran? 

The current economic squeeze demands a granular, strategic approach to cost management. Solutions that provide an incomplete picture leave your fleet blind: simply recording that an engine idled provides incomplete and often misleading data. Without contextual data explaining why the idling occurred (was it for battery protection, cab comfort, or driver override), any policy adjustment or coaching advice is guesswork, leading to missed fuel savings and distrustful drivers. The optimal strategy for addressing this year’s top trucking industry concern (Economy) requires high-fidelity data that answers the “why.” 

Ask yourself:

  • How much data does our current tech stack leave falling through the gaps? 
  • How confident are you that your trucks deliver reliable data for effective coaching?
  • When we see unoptimal system use, is it an efficiency problem or a driver-comfort problem?

Optimal tech solutions provide reliable, high-fidelity data on all system activity, standardizing metrics across truck makes and models, and making it easy to coach drivers. Equipping your team with this level of transparency is key to driving fleet-wide efficiency.

GRADE YOURSELF: Pass/Fail

4. Can you instantly change settings for trucks remotely, or do you need shop visits to make adjustments?

Manual, truck-by-truck adjustments are the epitome of operational inefficiency. The labor required for individual shop visits, whether for seasonal changes, compliance updates, or simply correcting a setting, becomes a persistent and avoidable source of high non-fuel costs. 

Ask yourself:

  • When we need to change the engine warm-up threshold across our fleet for winter, how many technician hours does that consume?
  • If a new regulation is passed, how long does it take for us to ensure every truck is compliant?
  • How much revenue is lost when a truck is pulled into the shop simply to change seasonal settings?

Remote adjustments that allow you to fine-tune your fleet’s settings right from your desk could save you thousands in labor and downtime. 

GRADE YOURSELF: Pass/Fail

5. Do your current solutions report and standardize key data across all truck makes and models in your fleet?

Most fleets run a diverse mix of brands. Relying on manufacturer-specific systems creates data silos, preventing a unified, single view of fleet performance. These systems often measure different metrics or restrict data access, making fleet-wide standardization and coherent policy enforcement impossible. This compromises your ability to make data-driven decisions that reduce overall TCO.

Ask yourself:

  • How many platforms do our operations leaders have to check to get a holistic view of idle activity across the fleet?
  • Are we comparing apples to apples when looking at different truck brands’ idle reports?
  • Are we missing key efficiency opportunities because a portion of our fleet’s idle data is restricted by a manufacturer?

GRADE YOURSELF: Pass/Fail

6. If tariffs (or no tariffs) became long-term policy tomorrow, how would your fleet pivot its cost management strategy?

Economic volatility and the threat of increased tariffs on truck-tractors demand operational resilience. You cannot rely on unpredictable external factors. The strategic choice is investing in solutions that deliver quantifiable, consistent cost savings that insulate your bottom line from market volatility. 

Ask yourself:

  • What single-line-item operational cost could we confidently and immediately reduce to offset a major capital expenditure increase due to Tariffs?
  • How do our current solutions protect us against non-fuel costs?

GRADE YOURSELF: Pass/Fail

7. Have you quantified the added weight and diminished payload capacity imposed by your technology (e.g., APUs)?

For fleets with razor-thin operating margins or specialized loads, every pound matters. Diesel APUs can add hundreds of pounds of essentially dead weight that cut into revenue per mile by diminishing payload capacity on every single trip.

Ask yourself:

  • For our particular operation, how many dollars in revenue are we sacrificing per trip due to added weight?
  • If we adopted a lightweight, maintenance-free system, what would the cumulative gain in payload revenue be over a quarter?

GRADE YOURSELF: Pass/Fail

8. Are you confident that your current tech is designed to extend the lifespan of your engine and components, or is it exclusively for driver comfort?

With new equipment costs at record highs, asset preservation is critical. The newly ranked concern, Diesel Emissions Regulations, makes engine and aftertreatment maintenance increasingly expensive. If things like your idle management system merely ensure comfort without protecting the engine, it’s exposing you to major risks. 

Ask yourself:

  • Does our current tech prevent component wear and tear, or does it only react when the driver is uncomfortable?
  • How much are we spending annually on DPF maintenance that could be reduced by lowering unnecessary engine runtime?
  • Are we managing a comfort system or protecting a multi-thousand-dollar asset?

GRADE YOURSELF: Pass/Fail

9. How durable is your technology, given the ever-changing landscape of emissions regulations?

As per usual, the regulatory environment is volatile, with the EPA rescinding various vehicle emission rules this year. With loose guidelines that can change at any moment, you cannot afford to invest in new tech that must be ripped out or replaced every time the rules change. Ask yourself:

  • If a new state anti-idling law is passed tomorrow, how quickly can we push a new, compliant idle setting to every truck in that region?
  • Does our current system allow us to adjust emissions-related settings remotely, or does it require a costly shop visit?
  • How are we managing idle laws for trucks, as they vary by state? 

Investing in technology that works for any regulatory environment is worthwhile and more realistic than you may think. When purchasing new technology, consider solutions that give you remote, granular control, so you can instantly update parameters fleet-wide, granting operational stability and future-proofing your business against sudden regulatory shifts.

GRADE YOURSELF: Pass/Fail

Turning Diagnostics into Savings

If you reached the end of this assessment and answered “Fail” to more questions than you answered “Pass,” or if you felt deep uncertainty about your answers, your current solutions are likely not fully mitigating the top risks outlined in the ATRI report.

The majority of problems highlighted in this self-assessment, from sudden no-starts to excessive maintenance costs, wasted fuel, and data gaps, are directly linked to predictable, preventable deficiencies in technology.

The solution to the industry’s largest concerns starts with a reliable idle management system.

Idle Smart is a platform-based solution engineered to address the top threats to your fleet by:

  • Protecting Profits: Eliminating no-starts and providing a maintenance-free solution to halt the hemorrhaging of roadside and labor costs.
  • Driving Efficiency: Offering unified, high-fidelity data and remote customization across all OEMs, allowing you to cut idle time dramatically and coach drivers effectively.
  • Future-Proofing Assets: Providing proactive engine defense to protect your high-cost engines and meet emissions goals without sacrificing driver comfort.

It’s time to equip your operation with the tools needed to weather this uncertain market.

Next Step

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