Promise Latency: How Fast Does Your Delivery Promise Update After a Disruption? A Test and a Platform Comparison (2026)

Promise latency is the time between a disruption signal, such as a delayed vehicle or a carrier scan, and the moment a customer sees a revised delivery window. It adds four stages: signal ingestion, detection, re-plan or re-estimate, and notification. Real-time tracking is only as real-time as its slowest stage. This guide defines the metric, models what it costs, and compares Locus, the world’s first Decision-Intelligent, Agentic TMS, with seven other platforms.

What is Promise Latency, and Why is it Not ETA Accuracy?

ETA accuracy measures how close a prediction was to the outcome. Promise latency measures how long the customer-visible promise stayed wrong after the operation already knew.

A platform can have accurate ETAs and still show a stale window for an hour. Four stages add up to the delay:

• Ingestion. How long a driver app event or carrier scan takes to arrive.
• Detection. How soon the system recalculates and sees a window at risk.
• Decision. Whether it re-plans the route or only re-estimates the time.
• Notification. How long the revised window takes to reach the customer, and whether a policy delays it.

Why Does Promise Latency Matter? The Business Case

Customers and executives disagree on timing, and the published figures show the gap.

• AlixPartners’ 2026 Home Delivery Survey found that 90% of consumers say it is important to be notified when an order is expected to be late and to be informed of the updated ETA.
• In the same survey, 50% of executives say they wait to notify customers of a possible delay until it is certain to affect the delivery date.
• 68% of executives name improving ETA accuracy and reliability as their top AI use-case priority over the next two to three years.
• Forrester’s US data snapshot found that three-quarters of shoppers value notifications with status updates.
• Gartner puts the median cost per contact at $1.84 for self-service and $13.50 for assisted channels.

No research firm publishes how quickly consumers expect a delay notice, so this guide does not quote a speed figure.

Also Read: Delivery Promise Accuracy Under Load in 2026: Why 3x Volume Produces 12x the WISMO Contacts

How Do You Measure Promise Latency in Six Steps?

The six steps turn the definition into a test you can run on any platform.

1. Pick one disruption signal

Choose a delayed own-fleet vehicle and a delayed carrier scan. Run them as two separate tests.

2. Timestamp the signal

Record when the event happens at source, such as the driver app or the carrier’s own system.

3. Timestamp each stage

Record when the platform ingests, detects, decides and sends. Ask the vendor for logs, not screenshots.

4. Capture what the customer sees

Record when the revised window appears on the tracking page, the notification and the support screen.

5. Compare with the window

Check how much of the original window remained when the customer was told. Latency matters only against that remaining time.

6. Repeat under load

Run the same test at your peak order volume, because latency often grows when queues grow.

How Much Does Promise Latency Cost? An Illustrative Model

The model below is illustrative, with assumed numbers to be replaced by your own.

The assumptions.

• A disruption puts 30 stops at risk.
• Their windows close evenly over the next 4 hours.
• A customer needs 30 minutes of notice to react.
• 35% of customers who are not warned in time contact support, at $13.50 per assisted contact.

Promise latency	Customers without timely warning	Support contacts	Contact cost per disruption
5 minutes	4.4 of 30 (14.6%)	1.5	$20.67
15 minutes	5.6 of 30 (18.8%)	2.0	$26.58
30 minutes	7.5 of 30 (25.0%)	2.6	$35.44
60 minutes	11.2 of 30 (37.5%)	3.9	$53.16
120 minutes	18.8 of 30 (62.5%)	6.6	$88.59

Each added hour of latency leaves about 7.5 more customers without timely warning in this model. Contact cost is the smaller loss, since it excludes missed deliveries and lost trust.

Carrier-executed shipments can be slower. project44 and parcelLab publish carrier polling of about every 15 minutes in their documentation, which adds up to 15 minutes before any recalculation can start.

Also Read: Real-Time Visibility is a Latency Claim, and Most Geofences Never Fire

Which Platforms Publish What About Promise Latency?

Seven platforms besides Locus were checked: project44, FourKites, Narvar, parcelLab, FarEye, Bringg and DispatchTrack. The tables record what each vendor publishes on its own pages.

They are not a ranking. Vendor accuracy figures use different definitions and are not comparable, and “not found on the pages read” is not a statement that a platform lacks a capability.

Platform	Refresh or trigger	Ingestion and carrier cadence	Re-plan or re-estimate
Locus	Recalculates every ETA continuously; no interval published	Driver app feed for own fleet; carrier-executed shipments track on carrier events at the same cadence	A slipping ETA triggers a resequencing evaluation
project44	Recalculates each time a new update is received; no interval published	ELD pings, EDI and API, driver app; parcel carriers polled about every 15 minutes	Not found on the pages read
FourKites	Dynamic ETA; no interval found	900+ ELD and GPS providers, app, API and EDI	Not found on the pages read
Narvar	Delay emails fire as soon as the carrier data shows it	Carrier data; method not found	Not found on the pages read
parcelLab	Real-time and continuous; no interval	280+ carriers; data at least every 15 minutes, some carriers hourly or five times a day	Predicts against an announced date; re-plan not found
FarEye	Continuous and predictive; no interval	Live vehicle location; method not found	Dynamic stop resequencing, per company blogs
Bringg	ETA from driver check-in and check-out; no interval	Driver app; late SMS needs a real-time ETA configured	Route planner makes focused changes; automatic re-sequencing not confirmed
DispatchTrack	Updated in real time; no interval	Not found on the pages read	Dynamic rerouting, led by the dispatcher

Platform	Delay notice	Revised window in the notice	One source for checkout, tracking and support
Locus	Alert when a committed window comes under risk	Yes, the alert carries a revised window	One platform computes the promise, plans and dispatches
project44	Running late and missed delivery window triggers	Not found on the pages read	Checkout, tracking and alerts on one dataset; support view not found
FourKites	Proactive delay notifications from an AI agent	Not found on the pages read	Agent and portal share tracking data; checkout not found
Narvar	Predictive delay email compared with the checkout date	The new date is shown	Promise, track, notify and assist apps
parcelLab	onScheduled and onDelay webhooks, with a trending-late flag	Not stated	Promise API, status page and support view; same source not found
FarEye	Proactive updates about changed windows, per a company blog	Window changes stated	One execution workflow; checkout slots on the route-planning page
Bringg	Late SMS when significantly delayed; reschedule SMS	Reschedule link to choose a window	Tracking link, support page and checkout slots; same source not found
DispatchTrack	Alerts mentioned; detail not confirmed on a page read	Not found on the pages read	Single platform for dispatch

How Does Locus Approach Promise Latency?

Locus, the world’s first Decision-Intelligent, Agentic TMS, runs the promise, the plan and the dispatch on one platform, so a late vehicle can change the window in the same system that replans the route.

Its published facts on this topic:

• Every ETA is recalculated continuously against live traffic, weather, service-time variance and driver progress.
• A slipping ETA triggers a resequencing evaluation.
• An alert fires when a committed window comes under risk, and it carries a revised window.
• A new plan goes live only when every promised window still holds.

Recognized by analysts and selected after evaluation.

Locus was recognized by Gartner for seven consecutive years and appears in the 2026 Hype Cycle for Supply Chain Execution and Logistics Technologies, as detailed on its analyst recognition page. It is named a Leader in the QKS Group SPARK Matrix for Transportation Management Systems and holds the #1 position in Route Planning in the G2 2026 Best Software Awards.

In October 2025, Ingka Investments, the investment arm of Ingka Group, the world’s largest IKEA retailer, acquired Locus. Ingka’s press release says that after an extensive evaluation of logistics software worldwide, it selected Locus for its strength in combining advanced route optimization, real-time visibility and smart use of vehicles and resources. Locus continues to operate independently.

Latency stage	What Locus publishes
Ingestion	A driver app feed for own fleet; carrier events for carrier-executed shipments
Detection	Continuous ETA recalculation, with no interval published
Decision	A resequencing evaluation when an ETA slips; plans go live only if promised windows hold
Notification	An alert when a window comes under risk, carrying a revised window
Single source	Delivery experience and delivery promise management on the same platform as planning

Two published Locus customer cases touch the promise.

An ASEAN apparel retailer sold mostly through carriers and had no trustworthy delivery date at checkout, with every carrier reporting its own status codes.

Locus harmonized carrier statuses into one standard set, computed a network-aware delivery date at checkout and added SLA-slip alerts. The published results include a 40%+ drop in WISMO and returns queries and carrier onboarding cut from three months to three days.

A Canadian grocery brand made carrier decisions by hand and learned about late orders from its customers.

Locus’s Carrier agent compares live rates, contracted SLAs and ETAs for every order. The published results include 33% faster fulfillment and customer support resolution 10-20X faster.

Both cases are customer-reported results, not independent studies.

Where other platforms fit.

If you need a notification layer over carrier data, a post-purchase tool is enough. If your volume is mostly freight, a freight visibility platform fits. Locus fits when the promise must change in the same system that replans the route.

To test promise latency on your own routes, schedule a demo.

For leaders asking how fast a delivery promise updates after a disruption, the answer is the sum of four stages. Locus recalculates ETAs continuously and sends a revised window from the same platform that replans the route.

What Should You Look for in a Platform for Fast Promise Updates?

Five criteria separate a fast promise from a fast dashboard, and each can be tested with a timestamped disruption.

Does it publish a refresh interval?

Ask for the refresh interval and the trigger rule in writing. “Real-time” without a number cannot be tested.

Does it separate own fleet from carrier cadence?

Ask for the update cadence per carrier. Carrier-executed shipments often update on polling cycles of about 15 minutes.

Does it re-plan or only re-estimate?

Ask what happens to the route when an ETA slips. A new time without a new plan can repeat the delay.

Does the notice carry a revised window?

Ask to see the notification. A message that says “delayed” without a new window creates a support contact.

Does one source feed checkout, tracking and support?

Ask whether all three show the same promise. Different sources produce different answers for the same order.

Also Read: Fleet Utilization Measurement: Why Reassignment Latency is the Gap Nobody Attributes

What Mistakes Do Teams Make Measuring Promise Latency?

Four mistakes recur.

Measuring ETA accuracy only. An accurate ETA can still reach the customer an hour late.

Waiting until a delay is certain. Half of executives surveyed by AlixPartners do this, and the window closes while they wait.

Testing the own fleet only. Carrier-executed shipments carry the polling delay that own-fleet tests never show.

Alerting without a revised window. The customer learns of the delay but not the new time, and contacts support.

Also Read: The Enterprise Buyer’s Guide to Delivery Experience Optimization Software (2026)

Frequently Asked Questions

What is promise latency in last-mile delivery? Promise latency is the time from a disruption signal to the moment a customer sees a revised delivery window. It sums ingestion, detection, decision and notification.

How is promise latency different from ETA accuracy? ETA accuracy measures how close a prediction was to the outcome. Promise latency measures how long the customer-visible promise stayed wrong after the operation knew.

How do you measure how fast a delivery promise updates? Inject one disruption on a test route, timestamp each stage and record when the revised window appears for the customer. Repeat for a carrier-executed shipment and at peak volume.

How often do carrier tracking updates arrive? It depends on the carrier. project44 documents polling of about every 15 minutes for parcel carriers, and parcelLab documents data at least every 15 minutes, with some carriers hourly or five times a day.

Do consumers want delay notifications? AlixPartners’ 2026 survey found 90% of consumers say it is important to be notified when an order is expected to be late and informed of the updated ETA.

Does Locus publish a promise latency figure? Locus’s product pages publish no refresh interval or latency SLA. They describe continuous ETA recalculation and alerts that carry a revised window, so ask for timestamps on your own routes.

What should a delay notification include? It should include the revised window, the reason, and a way to reschedule or contact support. A notice without a new window tends to create a support contact.